WO2023217793A1

WO2023217793A1 - Blood filtration device and blood filtration and blood plasma collection system

Info

Publication number: WO2023217793A1
Application number: PCT/EP2023/062298
Authority: WO
Inventors: Thomas Olund CHRISTENSEN; Peter Warthoe
Original assignee: Qlife Aps
Priority date: 2022-05-10
Filing date: 2023-05-09
Publication date: 2023-11-16

Abstract

A blood filtration device (10) is described. The device comprises a layered construction comprising a collection layer (40, 140) or collection layer structure arranged between a first layer structure (30, 130) and a second layer structure (50, 150). The collection layer (40, 140) comprises an aperture (42, 142) such that a collection volume (42', 142') is formed between the first layer structure (30, 130) and the second layer structure (50, 150). The collection layer (40, 140) further comprises a channel (44, 144) extending between the collection volume (42', 142') and a periphery (46, 146) of the collection layer (40, 140). The first layer structure (30, 130) comprises a blood plasma filter (32, 132), which is arranged to communicate with the collection volume (42', 142'). The second layer structure (50, 150) optionally comprises an air ventilation filter (52, 152) arranged to communicate with the collection volume.

Description

Title: Blood filtration device and blood filtration and blood plasma collection system

Field of the Invention

The present invention relates to a blood filtration device, a blood filtration and blood plasma collection system, a blood plasma collection device, and a kit of parts comprising a blood filter device and a blood plasma collection device.

Background of the Invention

Analysing the components of blood is a key diagnostic test in the detection of deceases. Accurate separation of plasma from the blood cells plays a crucial role in the precision of such diagnostic tests because the separation of the plasma minimises the interference of blood cells in analyte detection while improving sensitivity and selectivity.

Blood plasma can be separated from a blood sample by mechanical methods using sedimentation or centrifugation, which requires the use of laboratory equipment. It is also known to use separation pads or filters as well as devices based on microfluidic channels for separating the plasma from the blood sample.

However, existing system are encumbered by being complicated and expensive. Further, the existing systems are further encumbered by having inclusion of gasses, such as air bubbles, in the blood plasma, which makes it difficult and even impossible to obtain an accurate volume for the blood plasma sample. Thus, the variation in collected plasma will influence the sensitivity and accuracy of the diagnostic tests.

Accordingly, there is a need for inexpensive systems that are simple to use, and which ensure that accurate blood plasma can be collected without the inclusion of gasses, such as air bubbles.

Summary of the Invention

It is an object of the invention to obtain devices and systems, which overcome or ameliorate at least one of the disadvantages of the prior art or which provide a useful alternative.

According to a first aspect, this is obtained by a blood filtration device comprising: a layered construction comprising a collection layer structure, such as a collection layer, arranged between a first layer structure and a second layer structure; wherein the collection layer structure comprises an aperture such that a collection volume is formed between the first layer structure and the second layer structure, and wherein the collection layer structure further comprises a channel extending between the collection volume and a periphery of the collection layer structure; and wherein the first layer structure comprises a blood plasma filter, which is arranged to communicate with the collection volume.

Accordingly, it is seen that the blood filtration device comprises a collection volume that is formed in the layered structure, and where the blood filter is configured to filter blood that comes into contact with the filter and separate the blood plasma from the blood, and which is entering into the collection volume. By using a layered construction, the size of the collection volume can be made flexible. The first layer structure may for instance contact the second layer structure at the beginning of the process of filling the collection volume, e.g. by the blood plasma filter contacting the second layer structure. As the blood plasma fills into the volume, the flexible, first layer structure and the flexible, second layer structure expand or move apart, which ensures that no gasses, such as air bubble, are included in the blood plasma. The construction allows for the activation of the blood plasma filter by the blood plasma filter initially contacting the second layer structure. This is typically required in order for the blood plasma filter starting to filter the blood plasma from the blood sample. The above may be ensure by applying pressure to the first layer structure, e.g. by a pressure chamber containing the blood sample being formed to communicate with the blood plasma filter.

An air ventilation filter, such as a semipermeable membrane, enhances the effect by possible gasses being removed from the collection volume and the blood plasma. In some embodiments, it is envisaged that the device will function adequately without the semipermeable membrane, because a collapsed initial state may be sufficient to ensure that the gas is removed or pushed out of the channel as the blood plasma fills into the collection volume. In other words, it is contemplated that the second layer structure may be provided without the semipermeable membrane. In addition, it has been found for relatively small volumes for the collection volume that such configurations will not generate gasses, such as air bubbles, in the collected blood plasma.

The above in turn ensures that the blood plasma can be collected from the channel without any inclusion of gasses, such as air bubbles. Thereby, a very accurate volume of the blood plasma can be collected from the blood filtration device without any gasses at the channel that extends to the periphery of the collection layer or collection layer structure, thus ensuring that accurate diagnostic tests can be carried out on the collected blood plasma. The blood plasma filter may for instance be a Vicid™ plasma separation membrane from Pall Corporation, which comprises an asymmetric membrane. This asymmetry of this membrane enables the capture of whole cells for the generation of blood plasma without the need for cell removal by for instance centrifugation.

The layered construction is preferably a laminate construction.

It is noted that the collection layer structure may be formed as a single collection layer. In such a configuration, the collection volume and the channel may be formed in a single collection layer. However, the collection volume and the channel may also be formed in separate layers of the collection layer structure. In the following, the description both refers to a collection layer and a collection layer structure, recognising that the collection layer structure may be formed by one, two or even more layers.

According to a preferred embodiment, the first layer structure and the second layer structure are flexible. Preferably, the flexible structures are configured such that the blood plasma filter contacts the second layer structure as blood plasma begins to fill into the collection volume and are further configured to expand as blood plasma fills the collection volume.

According to a second aspect, there is provided a blood filtration device comprising: a housing, wherein a blood plasma separation configuration is arranged in the housing, the blood plasma configuration being configured to separate blood plasma from a blood sample and leading separated blood plasma to a channel, wherein the housing comprises a receptacle for receiving a blood plasma collecting device such that a collection end of the blood plasma collecting device is arranged at the channel.

Thus, the blood filtration device is configured to accommodate a blood plasma collecting device, which subsequently can be removed once the required amount of blood plasma has been collected. The blood plasma collecting device may for instance comprise a capillary tube with a known internal volume, whereby a very accurate blood plasma sample without air or gasses can be collected.

According to a third aspect, there is provided a blood filtration device comprising: a housing, wherein a blood plasma separation configuration is arranged in the housing, the blood plasma configuration being configured to separate blood plasma from a blood sample, wherein a blood well for collection of a blood sample is formed in the housing, wherein the blood well is arranged to communicate with the blood plasma filter, wherein the blood filtration device further comprises a lid, which is configured to provide a sealing connection to the housing so as to form a sealed volume at the blood well. The sealing connection provides a predetermined pressure to the sealed volume, preferable a slight over-pressure in the blood well as the lid is closed onto the housing. This slight over-pressure will start forcing the blood sample through the blood plasma filter. Since the blood sample typically will only fill a small part of the sealed volume, it is only necessary to displace a small volume of air in order to start forcing the blood sample through the blood plasma filter. Accordingly, it is ensured that the blood sample is not forced through the blood plasma filter with too high a force, which in itself could create air or gasses to be formed in the collected blood plasma, or which could cause blood cells to be pushed into the collection chamber. The pressure level in the sealed volume is kept substantially constant through the filtration process. The solution also ensures that a user of the device will have little or no influence on the pressure level formed in the sealed volume.

In a preferred embodiment, the sealed volume is configured to force the blood sample through the blood plasma filter with a pressure of 100-9,000 Pa, preferable by a pressure of 2,000-9,000 Pa, e.g. around 6,500 Pa. A too low pressure will not be sufficient to start the filtering process. However, a too high pressure, such as 10,000 Pa, may force other blood components through the blood plasma filter and potentially contaminate the blood plasma sample.

While the above embodiments have been described by having a pressure chamber to force the blood through the plasma filter, it is recognised that the same effect can also be achieved by providing an under-pressure in the collection volume. Suction may for instance be applied to the semipermeable membrane and/or to the channel formed in the collection layer or collection layer structure.

In the following, various embodiments are described that are applicable to any of the above- mentioned aspects.

According to a preferred embodiment, the first layer structure is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material. The first layer structure may comprise a number of separate parts, e.g. formed as separate layers. In another preferred embodiment, at least one of the separate parts of the first layer structure is made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate. In yet another preferred embodiment, the first layer structure comprises a primary layer made of a flexible material, such as a flexible polymer material or an elastomeric material, an optional liner, and the blood plasma filter, optionally with a double-adhesive layer arranged between the primary layer and the liner. The double-adhesive layer may for instance be a double-sided tape, e.g. comprising a polyethylene layer with a pressure sensitive synthetic rubber adhesive. Such products are commercially available e.g. from 3M Medical Tape 1510. In one advantageous embodiment, the primary layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm. Alternatively or in addition hereto, the double-adhesive layer may have a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

Similar considerations apply to the second layer structure. In a preferred embodiment, the second layer structure is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material. The second layer structure comprises a number of separate parts, e.g. formed as separate layers. In another preferred embodiment, at least one of the separate parts of the second layer structure is made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate. In yet another preferred embodiment, the second layer structure comprises a primary layer made of a flexible material, e.g. a flexible polymer material or an elastomeric material, an optional liner, and the air ventilation filter, optionally with a double-adhesive layer arranged between the primary layer and the air ventilation filter, alternatively between the primary layer and the optional liner. The double-adhesive layer may for instance be a double-sided tape, e.g. comprising a polyethylene layer with a pressure sensitive synthetic rubber adhesive. Such products are commercially available e.g. from 3M Medical Tape 1510.

In one advantageous embodiment, the primary layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm. Alternatively or in addition hereto, the double-adhesive layer may have a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

By letting the second layer structure and/or the first layer structure at least partly be made up of a flexible material, it is ensured that the layer structure(s) will adjust the size of collection volume as the blood component fills the collection volume and is forced into the channel. The above embodiments provide simple designs for providing layer structures that allow the size of the collection volume to adjust. As already explained, the flexible layers allow the first layer structure to for instance contact the second layer structure at the beginning of the process of filling the collection volume, e.g. by the blood plasma filter contacting the second layer structure. As the blood plasma fills into the volume, the flexible, first layer structure and the flexible, second layer structure expand, which ensures that no gasses, such as air bubble, are included in the blood plasma.

In a preferred embodiment, the air ventilation filter is a semipermeable membrane, such as a hydrophobic membrane that allows gasses to pass through the membrane but does not allow the blood component to pass through the membrane. This provides a simple solution for further separating air or gasses from the blood plasma. As the blood plasma starts to fill the collection volume, the collection volume is simultaneously evacuated for air and gasses by forcing them through the semipermeable membrane.

The blood plasma filter may advantageously comprise a separation membrane and a spreading layer configured for spreading a blood sample to cover the separation membrane. Thereby, it is ensured that a collected blood sample spreads across the separation membrane for effective separation of the blood plasma. This also ensures that the blood sample needs not be accurately applied to the blood plasma filter but only needs to contact the blood plasma filter.

In another advantageous embodiment, the blood plasma filter has a maximum outer dimension, such as a diameter, of 3-20 mm, preferably 5-18 mm, more preferably 8-15 mm, such as around 12 mm. This allows for an efficient performance of the filter and to fill the collection volume.

In a preferred embodiment, the collection layer or collection layer structure is at least partly made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate. The collection layer or collection layer structure may for instance be formed by a double-adhesive layer, such as a double-sided tape. The double-sided tape may comprise a polyethylene layer with a pressure sensitive synthetic rubber adhesive. Such products are commercially available e.g. from 3M as Medical Tape 1510. This provides a further simple design for forming the collection volume in the layered construction.

The collection layer or collection layer structure advantageously has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm. Alternatively or in addition hereto, the aperture of the collection layer or collection layer structure may have a maximum inner dimension, such as a diameter, of 3-15 mm, preferably 4-12 mm, more preferably 5-10 mm. This provides for suitable dimensions for collection of blood plasma. The collection volume, when filled with blood plasma, may advantageously have a volume of 5-15 ml. As previously mentioned, the collection volume may be collapsed before the blood plasma is filled into the volume. This configuration has a relatively large collection volume and favours the use of the air ventilation filter, such as a semipermeable membrane, to assist in ensuring that no gasses are included in the collected blood plasma.

However, the collection volume may also have a relatively small volume, which in itself has been found to avoid that gasses are included in the collected blood plasma. Thereby, the use of an air ventilation filter, such as a semipermeable membrane, may not be necessary. Again, the collection layer or collection layer structure advantageously has a thickness of 0.01-0.3 mm, preferably 0.02- 0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm or 0.15 mm. Alternatively or in addition hereto, the aperture of the collection layer or collection layer structure may have a maximum inner dimension, such as a diameter, of 0.1-5 mm, preferably 0.3-4 mm, more preferably 0.5-3 mm. The collection volume, when filled with blood plasma, may advantageously have a volume of 0.1-2 ml, e.g. around 1 ml.

In a preferred embodiment, the channel in the connection layer has a width of 0.1-2.0 mm, preferably 0.3-1.5 mm, more preferably 0.5-1.0 mm. These dimensions have been found to be highly suitable for leading the blood plasma from the collection volume and through the channel to a blood plasma collection device, e.g. a capillary tube, without air or gasses included in the blood plasma.

In a preferred embodiment, the blood filtration device further comprises a housing, and the layered construction is arranged in the housing. This allows the system to easily be handled by a user. In another preferred embodiment, a blood well for collection of a blood sample is formed in the housing, wherein the blood well is arranged to communicate with the blood plasma filter. This allows for efficient collection of a user's blood and for it to be led to the blood plasma filter and then into the collection volume.

As mentioned above, in a preferred embodiment, the housing comprises a receptacle for receiving a blood plasma collecting device such that a collection end of the blood plasma collecting device is arranged at the channel of the collection layer or collection layer structure. Thus, the blood filtration device is configured to accommodate a blood plasma collecting device, which subsequently can be removed once the required amount of blood plasma has been collected. The blood plasma collecting device may for instance comprise a capillary tube with a known internal volume, whereby a very accurate blood plasma sample without air or gasses can be collected.

In yet another preferred embodiment, a wiping material is arranged in (alternatively at or near) the receptacle, wherein the wiping material is arranged and configured to remove excess blood plasma from the blood plasma collecting device, when it is removed from the receptacle. The excess blood plasma may for instance be blood plasma that has been deposited on an exterior of the blood plasma collecting device. The wiping material may for instance be arranged so as to surround the capillary tube, when the blood plasma collecting device is inserted in the receptable. As the blood plasma collecting device with the capillary tube is removed from the receptacle, the wiping material removes the excess blood plasma, such as a possible blood plasma drop adhering to the end of the capillary tube. The wiping material may for instance be a polymer material, such as a foamed polymer. It may also be a glass fibre sheet, a hydrophilic porous structure, or paper. In another configuration, the wiping material is arranged to remove excess blood plasma from one or both ends of a capillary tube of the blood plasma collection device. The latter can for instance be carried out if the capillary tube is oriented substantially orthogonal to the insertion/removal direction of the blood plasma collection device when inserted or removed from the receptacle.

As mentioned above, the blood filtration device advantageously further comprises a lid, which is configured to provide a sealing connection to the housing so as to form a sealed volume at the blood well. The sealing connection provides a predetermined pressure to the sealed volume, preferable a slight over-pressure in the blood well as the lid is closed onto the housing. This slight over-pressure will start forcing the blood sample through the blood plasma filter. Since the volume of the sealed volume at the blood well will typically be much larger than the volume of the blood sample, the blood sample is not forced through the blood plasma filter with too high a force, which in itself could create air or gasses to be formed in the collected blood plasma, and further the pressure level in the sealed volume is kept substantially constant through the filtration process. The solution also ensures that a user of the device will have little or no influence on the pressure level formed in the sealed volume. Therefore, according to a preferred embodiment, the sealing connection between the housing and the lid is configured to provide an over-pressure at a sealed volume at the blood well.

In one preferred embodiment, the lid and the blood well are configured to form a sealing connection in an interior part of the blood well, e.g. via a sealing lip or ring formed in the lid or in the interior of the blood well. This provides a first simple embodiment for forming the sealing connection.

In another preferred embodiment, the housing comprises a protrusion, wherein the blood well is formed with the protrusion, and wherein the lid is configured to fit to an exterior part of the protrusion such that the sealing connection is formed between an interior part of the lid and the exterior part of the protrusion, e.g. via a sealing lip or ring formed in the lid or at the exterior part of the protrusion. This provides another simple embodiment for forming the sealing connection.

In both embodiments, the over-pressure is formed when the lid is inserted in or over the blood well as the lid is further inserted in the blood well or over the protrusion.

In a preferred embodiment, the lid comprises an interior pressure membrane that covers a top part of the lid. The interior pressure membrane ensures that the pressure in the sealed volume is maintained and is not influenced by a user pressing on the top part of the lid. The top part of the lid is preferably made of a relatively inflexible material, which also ensures that pressure applied to the top part of the lid does not influence the pressure in the sealed volume. In an advantageous embodiment, the lid is connected to a housing via a flap such that the lid can only be connected to the housing in a single manner. This further ensures that the user does not has influence on the pressure in the sealed volume.

In one advantageous embodiment, the blood filtration device comprises a blood indicator, which is arranged to communicate with the blood plasma filter and is configured to indicate when the blood plasma filter has been filled or saturated with a blood sample. The blood indicator may be part of the same filter but arranged outside of an exposed area of the blood plasma filter. Alternatively, the blood indicator may be a separate device and arranged to communicate with the blood plasma filter. The blood indicator may for instance be visible through a window or an opening in the housing. Once the blood indicator shows that blood from a blood sample has propagated to the blood indicator, the user is provided with visual evidence that a sufficient blood sample has been collected for providing filtering and collection of blood plasma. The user is thus provided with a visual indication that the lid may be closed, ensuring that the blood plasma is forced through the blood plasma filter and into the collection volume.

In another advantageous embodiment, the blood filtration device further comprises a plasma sample indicator arranged and configured to indicate when a collection volume, e.g. a capillary tube, of the blood plasma collection device has been filled.

According to a fourth aspect, there is provided a blood filtration and blood plasma collection system comprising a blood filtration device according to any of the above-mentioned embodiments, and a removable blood plasma collection device connected to the blood connection device. This allows for a system, where an accurate blood plasma sample can be collected and transferred to a setup for analysis or diagnostics of the blood plasma. Preferably, the blood plasma collection device is received in the receptacle of the blood filtration device.

The blood plasma collection device preferably comprises a capillary tube, wherein the blood plasma collection device is configured such that a first end of the capillary tube is arranged at the channel at the periphery of the collection layer or collection layer structure, when the blood plasma collection device is positioned in the receptacle of the blood filtration device.

According to an advantageous embodiment, the plasma sample indicator is arranged to communicate with a second end of the capillary tube, e.g. arranged in direct contact with the second end of the capillary tube or connected via a channel. Thus, the plasma sample indicator is arranged to be contacted by blood plasma once the capillary tube has filled from the first end to the second end. In another advantageous embodiment, the plasma sample indicator is arranged to communicate with an auxiliary channel, wherein the auxiliary channel has an end arranged at the channel at the periphery of the collection layer or collection layer structure. The capillary forces ensure that the blood plasma that is supplied by the channel of the collection layer or collection layer structure is first supplied into the capillary tube. Once the capillary tube has filled, the forces will start forcing the blood plasma into the auxiliary channel and into contact with the plasma sample indicator. Thus, the user is provided with a visual indication of the capillary tube having filled and that the blood plasma collection device may be removed from the receptacle. This configuration may be advantageous over the aforementioned embodiment because the capillary forces may make it slow for the blood plasma to exit from the second end of the capillary tube.

According to a fifth aspect, there is provided a blood plasma collection device comprising: a capillary tube comprising a first end for collecting blood plasma and a second end, a holder for holding the capillary tube, and preferably a handle connected to the holder.

In one embodiment, the handle is arranged proximal to the second end of the capillary tube. In another embodiment, the holder and optional handle are oriented in a direction that is substantially orthogonal to an orientation of the capillary tube.

The blood plasma collection device may advantageously be configured to be received in a receptacle of a blood filtration device according to any of the above-mentioned embodiments.

Thus, the blood plasma collection device is preferably configured for removable connection with the blood filtration device.

The holder may advantageously be attached to an exterior portion of the capillary tube. This provides for a simple design for holding the capillary tube.

Further, the holder comprises an exterior seal, such as a sealing ring, preferably arranged near the handle, e.g. at the second end of the capillary tube. The exterior seal is preferably arranged and configured such that the capillary tube and holder can be inserted sealingly into a test tube or a similar test setup.

In another advantageous embodiment, the holder has a weak point such that the handle can be broken off from the blood plasma collection device. In accordance with the above and according to a sixth aspect, there is also provided a kit of parts comprising: a blood filter device according to any of the above-mentioned embodiment, and a blood plasma collection device according to any of the aforementioned embodiments.

In the above, the invention has been explained in relation to blood samples and the use of a blood plasma filter to facilitate the collection of a blood plasma sample. However, it is also recognised that the devices and system may be utilised for other types of samples, such as saliva. In particular, the collection device may be used for collecting other types of samples, such as a saliva sample. Accordingly, the collection device according to the fifth aspect may broadly be referred to as a sample collection device. The sample collection device may be provided with any of the features described above, such as a capillary tube, a holder for holding the capillary tube, and preferably a handle connected to the holder. In addition, it may be provided with any of the features that are explained in the aforementioned embodiments.

In the following, preferred embodiments according to the above aspects are described. The various embodiments relate to any of the above aspects and may be combined in any conceived combination.

Brief Description of the Figures

The invention is explained in detail below with reference to embodiments shown in the drawings, in which

Fig. 1 shows a first perspective view of a blood filtration and blood plasma collection system,

Fig. 2 shows a second perspective view of the blood filtration and blood plasma collection system shown in Fig. 1,

Fig. 3 shows an exploded view of a first embodiment of a layered construction,

Fig. 4 shows an exploded view of a second embodiment of a layered construction,

Fig. 5 shows a top view of the blood filtration and blood plasma collection system,

Fig. 6 shows a partial cut-out view of the blood filtration and blood plasma collection system,

Fig. 7 shows top view of a blood plasma collection device, Fig. 8 shows a cross-sectional view of a lid connected to a blood filtration device,

Fig. 9 shows an exploded view of components of a second embodiment of a blood filtration and blood plasma collection system,

Fig. 10 shows a top view of a part of the second embodiment,

Fig. 11 shows a perspective view of parts of the second embodiment,

Fig. 12 shows a top view of parts of the second embodiment,

Fig. 13 shows an exploded view of an embodiment of a layered construction, e.g. for use in the second embodiment,

Figs. 14a-14c schematically illustrate steps in collecting a blood plasma sample,

Figs. 15a-15c show views of a third embodiment of a blood filtration and blood plasma collection system, and

Fig. 16 illustrates a collecting device with a snap lock.

Detailed Description of the Invention

In the following, a number of exemplary embodiments are described in order to understand the invention.

Fig. 1 shows a first perspective view of a blood filtration and blood plasma collection system. The blood filtration and blood plasma collection system comprises a blood filtration device 10 and a blood plasma collection device 70. As seen from the figure, the blood filtration device 10 comprises a housing. The housing 20 comprises a receptacle for receiving the blood plasma collection device 70. The housing also comprises a blood well 22 for collecting a blood sample from a user. In addition, it is seen that the blood filtration device 10 comprises a lid 60, which can be fitted to the blood well to form a sealing connection such that a sealed volume is formed between the lid 60 and the blood well 22. In the shown design, the lid 60 is connected to the housing 20 via a flap 66. This ensures that the lid 60 can only be sealed to the blood well in a single manner. However, the flap is not critical for the blood filtration device 10, and accordingly it is envisaged to provide the blood filtration device without the flap 66. Further, it is seen that there is a blood plasma filter at the bottom of the blood well 22.

Fig. 2 shows a second perspective view of a blood filtration and blood plasma collection system, in which the lid 60 has been sealed to the blood well 22 of the housing 20. Further, it is seen that the blood plasma collection device 70 has been removed from the receptacle of the blood filtration device 10. Accordingly, it is recognised that the blood plasma collection device 70 may be removably connected to the blood filtration device 10.

The blood filtration device 10 comprises a layered construction that is arranged within the housing 22.

Fig. 3 shows an exploded view of a first embodiment of the layered construction. The layered construction comprises a collection layer 40 arranged between a first layer structure 30 and a second layer structure 50. The collection layer 40 comprises an aperture 42 such that a collection volume 42' is formed between the first layer structure 30 and the second layer structure 50. The collection layer 40 further comprises a channel 44 extending between the collection volume 42' (or aperture 42) and a periphery 46 of the collection layer 40. The first layer structure 30 comprises a blood plasma filter 32, which is arranged to communicate with the collection volume 42'. The second layer structure 50 comprises an air ventilation filter 52 arranged to communicate with the collection volume 42' and configured for removing gasses from the collection volume 42'. The layered construction is preferably a laminate construction.

Accordingly, it is seen that the blood filtration device 10 comprises a collection volume 42' that is formed in the layered structure, and where the blood plasma filter 32 is configured to filter blood that comes into contact with the blood plasma filter 32 and separate the blood plasma from the blood, and which is entering into the collection volume 42'. By using a layered construction, the size of the collection volume can be made flexible. The first layer structure 30 may for instance contact the second layer structure 50 through the aperture 42 at the beginning of the process of filling the collection volume, e.g. by the blood plasma filter 32 contacting the second layer structure 50. As the blood plasma fills into the collection volume 42', the flexible, first layer structure 30 and the flexible, second layer structure 50 are moved apart such that the collection volume 42' expands, which ensures that no gasses, such as air bubble, are trapped or otherwise included in the blood plasma. The construction allows for the activation of the blood plasma filter 32 by the blood plasma filter 32 initially contacting the second layer structure 50. This is typically required in order for the blood plasma filter 32 starting to filter the blood plasma from the blood sample. The above may be ensure by applying pressure to the first layer structure 30, e.g. by a pressure chamber containing the blood sample being formed to communicate with the blood plasma filter.

The air ventilation filter, preferably in form of a semipermeable membrane, enhances this by possible gasses being removed from the collection volume 42' and the blood plasma.

The design ensures that the blood plasma can be collected from the channel 44 without any inclusion of gasses, such as air bubbles. Thereby, a very accurate volume of the blood plasma can be collected from the blood filtration device 10 without any gasses at the channel 44 that extends to the periphery 46 of the collection layer 40, thus ensuring that accurate diagnostic tests can be carried out on the collected blood plasma.

The blood plasma filter may for instance be a Vicid™ plasma separation membrane from Pall Corporation, which comprises an asymmetric membrane. This asymmetry of this membrane enables the capture of whole cells for the generation of blood plasma without the need for cell removal by for instance centrifugation.

As understood from the above, the first layer structure 30 and the second layer structure 50 are flexible. Preferably, the flexible structures are configured such that the blood plasma filter 32 contacts the second layer structure 50 as blood plasma begins to fill into the collection volume 42' and are further configured to expand or move apart as blood plasma fills the collection volume 42'.

The first layer structure 30 is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material. The first layer structure may, as shown in Fig. 3, comprise a number of separate parts, e.g. formed as separate layers. At least one of the separate parts of the first layer structure is made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene (PE) or polyethylene terephthalate (PET).

In the embodiment shown in Fig. 3, the first layer structure 30 comprises a primary layer 38 made of a flexible material, such as a flexible polymer material or an elastomeric material, a liner 34 and the blood plasma filter 32. Further, as shown, a double-adhesive layer 36 may be arranged between the primary layer 38 and the liner 34. The blood plasma filter 32 is connected to the liner 34.

The double-adhesive layer 36 may for instance be a double-sided tape, e.g. comprising a polyethylene layer with a pressure sensitive synthetic rubber adhesive. Such products are commercially available e.g. from 3M as Medical Tape 1510. The primary layer 38 may have a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm. It may be made of PE or PET. The double-adhesive layer 36 may have a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

Similar considerations apply to the second layer structure 50. In the embodiment shown in Fig. 3, the second layer structure 50 is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material. The second layer structure 50 comprises a number of separate parts, e.g. formed as separate layers. At least one of the separate parts of the second layer structure 50 is made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as PE or PET. As shown in the embodiment in Fig. 3, the second layer structure 50 comprises a primary layer 56 made of a flexible material, e.g. a flexible polymer material or an elastomeric material, an optional liner (not shown) and the air ventilation filter 52, e.g. with a double-adhesive layer 54 arranged between the primary layer 56 and the air ventilation filter 52, alternatively between the primary layer and the optional liner. The double-adhesive layer 54 may for instance be a doublesided tape, e.g. comprising a polyethylene layer with a pressure sensitive synthetic rubber adhesive. Such products are commercially available e.g. from 3M as Medical Tape 1510.

The primary layer 56 may have a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm. It may be made of PE or PET. The double-adhesive layer 54 may have a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

By letting the first layer structure 30 and the first layer structure 50 at least partly be made up of a flexible material, it is ensured that the layer structures 30, 50 will adjust the size of collection volume as the blood component fills the collection volume 42' and is forced into the channel 44. The above embodiments provide simple designs for providing layer structures that allow the size of the collection volume 42' to adjust. As already explained, the flexible layers allow the first layer structure 30 to for instance contact the second layer structure 50 at the beginning of the process of filling the collection volume, e.g. by the blood plasma filter 32 contacting the second layer structure 50. As the blood plasma fills into the volume 42', the flexible, first layer structure 30 and the flexible, second layer structure 50 expand or move apart, which ensures that no gasses, such as air bubble, are included in the blood plasma.

The air ventilation filter 52 is preferably a semipermeable membrane, such as a hydrophobic membrane, that allows gasses to pass through the membrane but does not allow the blood component to pass through the membrane. This provides a simple solution for further separating air or gasses from the blood plasma. As the blood plasma starts to fill the collection volume 42', the collection volume is simultaneously evacuated for air and gasses by forcing them through the semipermeable membrane 52.

The blood plasma filter 32 may advantageously comprise a separation membrane and a spreading layer configured for spreading a blood sample to cover the separation membrane. Thereby, it is ensured that a collected blood sample is spread across the separation membrane for effective separation of the blood plasma. This also ensures that the blood sample needs not accurately be applied to the blood plasma filter but only needs to contact the blood plasma filter 32.

The blood plasma filter preferably has a maximum outer dimension, such as a diameter, of 3-20 mm, preferably 5-18 mm, more preferably 8-15 mm, such as around 12 mm. This allows for an efficient performance of the filter and to fill the collection volume.

The collection layer 40 is preferably at least partly made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate. The collection layer may for instance be formed by a double-adhesive layer, such as a double-sided tape. The double-sided tape may comprise a polyethylene layer with a pressure sensitive synthetic rubber adhesive. Such products are commercially available e.g. from 3M as Medical Tape 1510. This provides a further simple design for forming the collection volume 42' in the layered construction.

The collection layer 40 advantageously has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm. The aperture 42 of the collection layer 40 may have a maximum inner dimension, such as a diameter, of 3-15 mm, preferably 4-12 mm, more preferably 5-10 mm. This provides for suitable dimensions for collection of blood plasma. The collection volume 42', when filled with blood plasma, may advantageously have a volume of 5-15 ml. As previously mentioned, the collection volume 42' may be collapsed before the blood plasma is filled into the volume.

The channel 44 in the connection layer preferably has a width of 0.1-2.0 mm, preferably 0.3-1.5 mm, more preferably 0.5-1.0 mm. These dimensions have been found to be highly suitable for leading the blood plasma from the collection volume 42' and through the channel 40 to the blood plasma collection device 70, e.g. comprising a capillary tube, without air or gasses included in the blood plasma. It is recognised that it is the flexibility of the layers in the layered structures that attributes to the functionality of collecting blood plasma without gas or air bubble being trapped in the blood plasma. Accordingly, it is possible to deviate from the embodiment shown in Fig. 3. As an example, Fig. 4 shows an exploded view of a second embodiment of a layered construction that is suitable for the blood filtration device 10 and in which like numerals refer to like parts of the first embodiment shown in Fig. 3. In the embodiment shown in Fig. 4, the layered construction comprises a collection layer 140 arranged between a first layer structure 130 and a second layer structure 150. The collection layer 140 comprises an aperture 142 such that a collection volume 142' is formed between the first layer structure 130 and the second layer structure 150. The collection layer further comprises a channel 144 extending between the collection volume 142' and a periphery 146 of the collection layer 140. The first layer structure 130 comprises a blood plasma filter 132, which is arranged to communicate with the collection volume 142'. The second layer structure 150 comprises an air ventilation filter 152 arranged to communicate with the collection volume 142' and configured for removing gasses from the collection volume 142'. The first layer structure 130 is made up of three parts, viz. a flexible layer 138, a liner 134, and the blood plasma filter 132. The second layer structure 150 is made up of three parts, viz. a flexible layer 156, a liner 154, and the air ventilation filter 152. The considerations for choice of materials and dimensions are identical to the first embodiment shown in Fig. 3.

As mentioned, the blood filtration device 10 comprises a housing 20, and the layered construction is arranged in the housing 20. The layered construction may for instance be designed as shown in the first embodiment in Fig. 3 or in the second embodiments in Fig. 4. This allows the system to easily be handled by a user. As shown in Fig. 1, a blood well 22 for collection of a blood sample is formed in the housing 20, wherein the blood well 22 is arranged to communicate with the blood plasma filter 32, 132. This allows for efficient collection of a user's blood and for it to be led to the blood plasma filter 32, 132 and then into the collection volume 42, 142'.

Further details of the blood filtration and blood plasma collection system will now be explained with reference to Fig. 5, which shows a top view of the blood filtration and blood plasma collection system, Fig. 6, which shows a partial cut-out view of the blood filtration and blood plasma collection system, and Fig. 7, which shows top view of a blood plasma collection device.

As explained earlier, the blood filtration device 10 of the system comprises a housing 20. The housing may for instance comprise a protrusion to form the blood well 22. The lid 60 may as shown in Fig. 5 be arranged on this protrusion to form a sealed volume between the lid 60 and the blood well 22. The lid 60 may be connected to the housing via a flap. As shown in Fig. 6, the layered construction including the collection layer 40 (or 140) is arranged in the housing 22. The aperture 42 (or 142) in the collection layer 40 (or 140) thus allows for a collection volume 42' (or 142') to be formed and which can communicate with the channel 44 to lead the blood plasma to the blood plasma collecting device 70 of the system.

As seen in Fig. 7, the blood plasma collection device 70 comprises a capillary tube 72 comprising a first end 73 for collecting blood plasma and a second end 75, opposite the first end 73, a holder 74 for holding the capillary tube 72, and a handle 78 connected to the holder 74, the handle being arranged proximal to the second end 75 of the capillary tube 72. The holder 74 is attached to an exterior portion of the capillary tube 72. This provides for a simple design for holding the capillary tube. Alternatively, the holder can be formed as a channel into which the capillary tube 72 can be inserted. Further, the holder 74 comprises an exterior seal 76, such as a sealing ring exterior to the second end 75 of the capillary tube 72. The exterior seal 76 is arranged and configured such that the capillary tube 72 and at least part of the holder 74 can be inserted sealingly into a test tube or a similar test setup. The holder 74 may have a weak point or area such that the handle can easily be broken off from the blood plasma collection device 70 after having been inserted in the test tube or test setup.

As shown in Figs. 5-7, the blood plasma collection device 70 is configured to be received in a receptacle of a blood filtration device 10. Accordingly, the blood plasma collection device 70 is configured for removable connection with the blood filtration device 10.

When the blood plasma collection device 70 is arranged in the receptacle of the blood filtration device 10, the first end 73 (or collection end) of the capillary tube is arranged near the opening of the channel 44 (or 144) such that blood plasma is transferred to and collected by the capillary tube 72. Thus, the blood filtration device 10 is configured to accommodate a blood plasma collecting device 70, which subsequently can be removed once the required amount of blood plasma has been collected.

As shown in Fig. 6, a wiping material 26 may arranged in or near the receptacle in the housing 20. The wiping material 26 is arranged and configured to remove excess blood plasma from the blood plasma collecting device 70, when it is removed from the receptacle. The excess blood plasma may for instance be blood plasma that has been deposited on an exterior of the blood plasma collecting device 70. The wiping material is preferably arranged so as to surround the capillary tube 72 when the blood plasma collecting device 70 is inserted in the receptable. As the blood plasma collecting device 70 with the capillary tube 72 is removed from the receptacle, the wiping material 26 removes the excess blood plasma, such as a possible blood plasma drop adhering to the end of the capillary tube 72. The wiping material may for instance be a polymer material, such as a foamed polymer, or any other material suitable for absorbing or otherwise removing the excess blood plasma. It may also be a glass fibre sheet, a hydrophilic porous structure, or paper.

As mentioned, the lid 60 and the housing 20 are mutually configured such that a sealed volume may be formed over the blood well 22. One example of a design for obtaining such a sealed volume is illustrated in Fig. 8, which shows a cross-sectional view of the lid 60 connected to the housing 20 of the blood filtration device 10.

As seen in Fig. 8, the housing comprises a protrusion 24, and the blood well 22 is formed with the protrusion. The lid 60 is configured to fit to an exterior part of the protrusion such that the sealing connection is formed between an interior part of the lid 60 and the exterior part of the protrusion 24. In the shown embodiment, a sealing bulge or sealing lip 64 is formed at the proximal end of the lid 60. However, the sealing may also be formed via a sealing ring or the like on an interior part of the lid 60 or at an exterior part of the protrusion 24. This provides for a simple embodiment for forming the sealing connection. In an alternative embodiment, the sealing may be formed between an exterior part of a lid and an interior part of the blood well.

In the shown embodiment, the lid 60 comprises an interior pressure membrane 62 that covers a top part of the lid 60. The interior pressure membrane 62 ensures that the pressure in the sealed volume is maintained and is not influenced by a user pressing on the top part of the lid 60. The top part of the lid 60 is preferably made of a relatively inflexible material, which also ensures that pressure applied to the top part of the lid does not influence the pressure in the sealed volume.

The sealing connection provides a predetermined pressure to the sealed volume, preferable a slight over-pressure in the blood well as the lid 60 is closed onto protrusion 24 of the housing 20. This slight over-pressure will start forcing the blood sample through the blood plasma filter 32 (or 132). Since the volume of the sealed volume at the blood well 22 will typically be much larger than the volume of the blood sample, it is ensured that the blood sample is not forced through the blood plasma filter 32, 132 with too large a force, which in itself could create air or gasses to be formed in the collected blood plasma, or which could cause blood cells to be pushed into the collection chamber 42', 142', which would contaminate the blood plasma sample. The pressure level in the sealed volume is kept substantially constant through the filtration process. The solution also ensures that a user of the device will have little or no influence on the pressure level formed in the sealed volume. The sealed chamber may be configured such that the blood sample is forced through the blood plasma filter at a pressure of 2,000-3,000 Pa. However, the pressure may also be higher, such as approximately 6,500 Pa. Fig. 9 shows an exploded view of parts of a second embodiment for a blood filtration and blood plasma collection system. The blood filtration and blood plasma collection system comprises a blood filtration device 210 and a blood plasma collection device 270. As seen from the figure, the blood filtration device 210 comprises a housing 220. The housing 220 comprises separate parts, such as a top part 220', a bottom part 220", and a support structure 227. The housing also comprises a blood well for collecting a blood sample from a user with a blood plasma filter arranged at the bottom of the well. The various housing parts form a receptacle that may receive the blood plasma collection device 270. Further, a wiping material 226 may be arranged in a housing 220, such that excess blood plasma may be wiped off the blood plasma collection device 270 when it is removed from the receptacle.

Fig. 10 shows a top view of the top part 220' of the housing 220. It is seen that the blood filtration device 210 comprises a blood well 222 and a lid 260, which can be fitted to the blood well 222 to form a sealing connection such that a sealed volume is formed between the lid 260 and the blood well 222. In the shown design, the lid 260 is connected to the housing 220 via a flap 266. This ensures that the lid 260 can only be sealed to the blood well 222 in a single manner. However, the flap is not critical for the blood filtration device 210, and accordingly it is envisaged to provide the blood filtration device without the flap 266. Further, it is seen that there is a blood plasma filter at the bottom of the blood well 222.

Fig. 13 shows an exploded view of an embodiment of the layered construction 212. The layered construction 212 comprises a collection layer 240 arranged between a first layer structure comprising an adhesive layer 236, and a second layer structure 250. The collection layer 240 together with a top layer 238 comprises an aperture 242 such that a collection volume 242' is formed between the first layer structure and the second layer structure 250. The collection layer 240 further comprises a channel 244 extending between the collection volume 242' (or aperture 242) and a periphery 246 of the collection layer 240. The first layer structure comprises a blood plasma filter 232, which is arranged to communicate with the collection volume 242'. In the shown embodiment, the second layer structure 250 does not comprise an air ventilation filter but this may optionally be added to the design. The layered construction is preferably a laminate construction. The layered construction 232 further comprises a blood indicator 229, which in the shown embodiment comprises an indication activation layer 233 and a collection indicator 235. This may for instance be implemented via a membrane as the indication activation layer 233 that is wetted to become transparent and revealing the collection indicator 235, which may be a coloured marking. The blood indicator 229 is arranged to communicate with the blood plasma filter and is configured to indicate when the blood plasma filter has been saturated with a blood sample. In an alternative embodiment, the blood indicator 229 may be part of the blood plasma filter 232 but arranged outside of an exposed area of the blood plasma filter 232. Alternatively, the blood indicator may as shown be a separate device and arranged to communicate with the blood plasma filter. The blood indicator 229 may for instance be visible through a window or an opening in the housing 220. Once the blood indicator 229 shows that blood from a blood sample has propagated to the blood indicator, the user is provided with visual evidence that a sufficient blood sample has been collected for providing filtering and collection of blood plasma. The user is thus provided with an indication that the lid 260 may be closed, ensuring that the blood plasma is forced through the blood plasma filter 232 and into the collection volume 242'. The material and dimensions, such as thicknesses, may be the same as for the embodiments shown in Fig. 3 and Fig. 4. However, in the embodiment shown in Fig. 13, it is seen that the collection volume 242' is smaller than in the embodiments of Figs. 3 and 4. This has in itself been found to avoid that gasses are included in the collected blood plasma. Thereby, the use of an air ventilation filter, such as a semipermeable membrane may not be necessary. Again, the collection layer or collection layer structure advantageously has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm or 0.15 mm. Alternatively or in addition hereto, the aperture 242 of the collection layer or collection layer structure may have a maximum inner dimension, such as a diameter, of 0.1-5 mm, preferably 0.3-4 mm, more preferably 0.5-3 mm. The collection volume, when filled with blood plasma, may advantageously have a volume of 0.1-2 ml, e.g. around 1 ml.

Figs. 11 and 12 show a perspective view and a top view, respectively, of parts of the second embodiment for a blood filtration and blood plasma collection system. In the shown embodiment, the blood plasma collection device 270 has a different design than the previously shown embodiment. The blood plasma collection device 270 comprises a capillary tube 272 comprising a first end 273 for collecting blood plasma and a second end 275, opposite the first end 273, a holder 274 for holding the capillary tube 272, and a handle 278 connected to the holder 274. The holder 274 is attached to an exterior portion of the capillary tube 272. This provides for a simple design for holding the capillary tube. Further, the holder 274 may comprise an exterior seal, such as a sealing, such that at least part of the holder 274 can be inserted sealingly into a test tube or a similar test setup. The holder 274 may have a weak point or area such that the handle can easily be broken off from the blood plasma collection device 270 after having been inserted in the test tube or test setup. In contrast to the previous embodiment, the capillary tube 272 and the holder are oriented approximately orthogonal to each other.

Further, it is seen that the blood filtration and blood plasma collection system comprises a wiping material 226 arranged in or near the receptacle of the housing 220. The wiping material 226 is arranged and configured to remove excess blood plasma from the blood plasma collecting device 270 when it is removed from the receptacle. The excess blood plasma may for instance be blood plasma that has been deposited on an exterior of the blood plasma collecting device 270. The wiping material 226 is arranged and configured such that it can remove excess blood plasma from both the first end 273 and the second end 275 of the capillary tube 272. As the blood plasma collecting device 270 with the capillary tube 272 is removed from the receptacle, the wiping material 226 removes the excess blood plasma, such as a possible blood plasma drop adhering to the end of the capillary tube 272, e.g. at the ends 273, 275. The wiping material may for instance be a polymer material, such as a foamed polymer, or any other material suitable for absorbing or otherwise removing the excess blood plasma. It may also be a glass fibre sheet, a hydrophilic porous structure, or paper. In the shown embodiment, the wiping material 226 is configured such that it extends beyond the two ends of the capillary tube 272. However, it is also possible to use two separately arranged wiping materials.

In addition, the system comprises a plasma sample indicator 280 arranged and configured to indicate when the capillary tube 272 of the blood plasma collection device 270 has been filled. The plasma sample indicator 280 is arranged to communicate with an auxiliary channel 282, wherein the auxiliary channel has an end arranged at the channel at the periphery 246 of the collection layer 240. The capillary forces ensures that the blood plasma that is supplied by the channel 244 of the collection layer 240 is first drawn into the capillary tube 272. Once the capillary tube has filled, the forces will start propagating the blood plasma into the auxiliary channel 282 and into contact with the plasma sample indicator 280. Thus, the user is provided with a visual indication of the capillary tube being filled and that the blood plasma collection device 270 may be removed from the receptacle.

Any of the various indicators 229, 280 may be a PH sensitive strip.

Figs. 14a-14c illustrate the principles of collecting a blood plasma sample using the system. Fig. 14a illustrates inter alia the blood plasma filter 232, the blood plasma indicator 280, and the capillary tube 272 before adding a blood sample to the system. Fig. 14b illustrates a blood sample being supplied to the blood plasma filter 232, which filters the blood sample and delivers the blood plasma to the collection volume and then to the channel 244 of the collection layer 240. Once the blood plasma reaches the first end 273 of the capillary tube 272, the capillary forces draw the blood plasma into the capillary tube. Once the blood plasma has filled the capillary tube 272 from the first end 273 to the second end 275, the forces will push blood plasma into the auxiliary channel 282 and bring the blood plasma into contact with the blood plasma indicator 280. The blood plasma indicator 280 reacts with the blood plasma and provides a visual indication to the user that the capillary tube 272 has been filled and that the plasma collection device 270 can be removed from the receptacle. Figs. 15a-15c show a third embodiment of a blood filtration and blood plasma collection system. The embodiment is used to illustrate that variants of the system can be contemplated. In the shown embodiment, like reference numerals refer to like parts of the aforementioned embodiments. Only the primary differences are described here. In the shown embodiment, the cap 360 is provided as a screw cap, which can be screwed onto the blood well 322. This configuration has also been found to be sufficient to provide the necessary forces to force the blood sample through the blood plasma filter. Similar to the previous embodiment, the system has a blood indicator 329. When the blood indicator 329 shows that the blood plasma filter has saturated, the cap 360 can be screwed onto the blood well. The shown embodiment also comprises a blood plasma collection device 370 similar to the previous embodiment with the capillary tube 372 arranged substantially orthogonal to the orientation of the blood plasma collection device 370. The embodiment differs from the previous embodiment in that the blood plasma indicator 380 is arranged on the other side of the capillary tube. Thus, blood plasma is provided from a channel of the blood filtration device and fed to the first end 372 of the capillary tube. Once the capillary tube 372 has filled, excess blood plasma may form at the second end 375 of the capillary tube. The second end may communicate with the blood plasma indicator 380 or be in direct blood plasma indicator. The blood plasma indicator 380 reacts with the blood plasma and provides a visual indication to the user that the capillary tube 372 has been filled and that the plasma collection device 270 can be removed from the receptacle.

While the invention has been explained in relation to specific examples, it is recognised that various modifications are foreseen without departing from the scope of the invention, which is defined by the claims. However, it is contemplated that at least the collection device may be used for collecting different types of samples, such as saliva samples. Further, the previous embodiments for the collecting device have been described as having a weak point such that the handle can easily be broken off after having been inserted into the test tube or test setup. However, in another advantageous embodiment, the holder or part of the holder may be configured with a snap lock 279 as shown in Fig. 16. This snap lock 279 may be released when it is inserted into the test tube or test setup, thus leaving that part of the collecting device in the test tube or test setup.

Exemplary embodiments

Exemplary embodiments of the present disclosure are set out in the following articles and items:

Articles

1. A blood filtration device (10) comprising: a layered construction comprising a collection layer structure (40, 140), such as a collection layer, arranged between a first layer structure (30, 130) and a second layer structure (50, 150); wherein the collection layer structure (40, 140) comprises an aperture (42, 142) such that a collection volume (42', 142') is formed between the first layer structure (30, 130) and the second layer structure (50, 150), and wherein the collection layer structure (40, 140) further comprises a channel (44, 144) extending between the collection volume (42', 142') and a periphery (46, 146) of the collection layer structure (40, 140); and wherein the first layer structure (30, 130) comprises a blood plasma filter (32, 132), which is arranged to communicate with the collection volume (42', 142').

2. The blood filtration device according to article 1, wherein the second layer structure (50, 150) comprises an air ventilation filter (52, 152) arranged to communicate with the collection volume (42', 142') and configured for removing gasses from the collection volume (42', 142').

3. The blood filtration device according to any of articles 1-2, wherein the collection volume and the channel are formed in a single collection layer.

4. The blood filtration device according to any of articles 1-2, wherein the collection volume and the channel are formed in separate layers of the collection layer structure.

5. The blood filtration device according to any of articles 1-4, wherein the first layer structure is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material.

6. The blood filtration device according to any of articles 1-5, wherein the first layer structure comprises a number of separate parts, e.g. formed as a separate layers.

7. The blood filtration device according to articles 6, wherein at least one of the separate parts of the first layer structure is made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

8. The blood filtration device according to any of articles 6-7, wherein the first layer structure comprises a primary layer made of a flexible material, such as a flexible polymer material or an elastomeric material, an optional liner, and the blood plasma filter, optionally with a double-adhesive layer arranged between the primary layer and the liner. 9. The blood filtration device according to article 8, wherein the primary layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm, and/or wherein the double-adhesive layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

10. The blood filtration device according to any of articles 1-9, wherein the second layer structure is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material.

11. The blood filtration device according to any of articles 1-10, wherein the second layer structure comprises a number of separate parts, e.g. formed as separate layers.

12. The blood filtration device according to any of articles 10-11, wherein at least one of the separate parts of the second layer structure are made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

13. The blood filtration device according to any of articles 10-12, wherein the second layer structure comprises a primary layer made of a flexible material, e.g. a flexible polymer material or an elastomeric material, an optional liner, and optionally the air ventilation filter, optionally with a double-adhesive layer arranged between the primary layer and the air ventilation filter, alternatively between the primary layer and the optional liner.

14. The blood filtration device according to article 13, wherein the primary layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm, and/or wherein the double-adhesive layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

15. The blood filtration device according to any of articles 1-14, wherein the air ventilation filter is a semipermeable membrane, such as a hydrophobic membrane that allows gasses to pass through the membrane but does not allow the blood component to pass through the membrane. 16. The blood filtration device according to any of articles 1-15, wherein the blood plasma filter comprises a separation membrane and a spreading layer configured for spreading a blood sample to cover the separation membrane.

17. The blood filtration device according to any of articles 1-16, wherein the blood plasma filter has a maximum outer dimension, such as a diameter, of 3-20 mm, preferably 5-18 mm, more preferably 8-15 mm, such as around 12mm.

18. The blood filtration device according to any of articles 1-17, wherein the collection layer or collection layer structure is at least partly made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

19. The blood filtration device according to article 18, wherein the collection layer or collection layer structure is formed by a double-adhesive layer, such as a double-sided tape.

20. The blood filtration device according to any of articles 1-19, wherein the collection layer or collection layer structure has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

21. The blood filtration device according to any of articles 1-20, wherein the aperture of the collection layer or collection layer structure has a maximum inner dimension, such as a diameter, of 3-15 mm, preferably 4-12 mm, more preferably 5-10 mm.

22. The blood filtration device according to any of articles 1-21, wherein the collection volume, when filled with blood plasma, has a volume of 5-15 ml.

23. The blood filtration device according to any of articles 1-20, wherein the collection layer or collection layer structure has a maximum inner dimension, such as a diameter, of 0.1-5 mm, preferably 0.3-4 mm, more preferably 0.5-3 mm.

24. The blood filtration device according to article 23, wherein the collection volume, when filled with blood plasma, has a volume of 0.1-2 ml, e.g. around 1 ml.

25. The blood filtration device according to any of articles 1-24, wherein the channel (44) in the connection layer (40) has a width of 0.1-2.0 mm, preferably 0.3-1.5 mm, more preferably 0.5-1.0 mm.

26. The blood filtration device according to any of articles 1-25, wherein the blood filtration device further comprises a housing, and wherein the layered construction is arranged in the housing.

27. The blood filtration device according to article 26, wherein a blood well (22) for collection of a blood sample is formed in the housing, wherein the blood well is arranged to communicate with the blood plasma filter (32).

28. The blood filtration device according to any of articles 26-27, wherein the housing comprises a receptacle for receiving a blood plasma collecting device such that a collection end of the blood plasma collecting device is arranged at the channel (44) of the collection layer or collection layer structure (40).

29. The blood filtration device according to article 28, wherein a wiping material (26) is arranged in the receptacle, wherein the wiping material is arranged and configured to remove excess blood plasma from the blood plasma collecting device, when it is removed from the receptacle.

30. The blood filtration device according to any of articles 27-29, wherein the blood filtration device further comprises a lid, which is configured to provide a sealing connection to the housing so as to form a sealed volume at the blood well.

31. The blood filtration device according to article 30, wherein the lid and the blood well are configured to form a sealing connection in an interior part of the blood well, e.g. via a sealing lip or ring formed in the lid or in the interior of the blood well.

32. The blood filtration device according to article 30, wherein the housing comprises a protrusion, wherein the blood well is formed with the protrusion, and wherein the lid is configured to fit to an exterior part of the protrusion such that the sealing connection is formed between an interior part of the lid and the exterior part of the protrusion, e.g. via a sealing lip or ring formed in the lid or at the exterior part of the protrusion. 33. The blood filtration device according to any of articles 30-32, wherein the lid comprises an interior pressure membrane that covers a top part of the lid.

34. The blood filtration device according to any of articles 30-33, wherein the lid is connected to a housing via a flap such that the lid can only be connected to the housing in a single manner.

35. The blood filtration device according to any of articles 1-34, wherein the blood filtration device comprises a blood indicator, which is arranged to communicate with the blood plasma filter and is configured to indicate when the blood plasma filter has been saturated with a blood sample.

36. The blood filtration device according to any of articles 1-35, wherein the blood filtration device further comprises a plasma sample indicator arranged and configured to indicate when a collection volume, e.g. a capillary tube, of the blood plasma collection device has been filled.

37. A blood filtration and blood plasma collection system comprising a blood filtration device according to any of articles 1-36, and a removable blood plasma collection device connected to the blood connection device.

38. The blood filtration and blood plasma collection system according to article 37, wherein the blood plasma collection device is received in the receptacle of the blood filtration device.

39. The blood filtration and blood plasma collection system according to article 38, wherein the blood plasma collection device comprises a capillary tube, and wherein the blood plasma collection device is configured such that a first end of the capillary tube is arranged at the channel at the periphery of the collection layer or collection layer structure, when the blood plasma collection device is positioned in the receptacle of the blood filtration device.

40. The blood filtration and blood plasma collection system according to article 39, wherein the plasma sample indicator is arranged to communicate with a second end of the capillary tube, e.g. arranged in direct contact with the second end of the capillary tube or connected via a channel.

41. The blood filtration and blood plasma collection system according to article 40, wherein the plasma sample indicator is arranged to communicate with an auxiliary channel, wherein the auxiliary channel has an end arranged at the channel at the periphery of the collection layer or collection layer structure. 42. A blood plasma collection device comprising: a capillary tube comprising a first end for collecting blood plasma and a second end, a holder for holding the capillary tube, and preferably a handle connected to the holder, e.g. wherein the blood plasma collection device is configured to be received in a receptacle of a blood filtration device according to any of articles 1-36.

43. The blood plasma collection device according to article 42, wherein the holder is attached to an exterior portion of the capillary tube.

44. The blood plasma collection device according to any of articles 42-43, wherein the handle is arranged proximal to the second end of the capillary tube.

45. The blood plasma collection device according to any of articles 42-44, wherein the holder and optional handle are oriented in a direction that is substantially orthogonal to an orientation of the capillary tube.

46. The blood plasma collection device according to any of articles 42-45, wherein the holder comprises an exterior seal, such as a sealing ring, preferably arranged near the handle, e.g. at the second end of the capillary tube.

47. The blood plasma collection device according to any of articles 42-46, wherein the holder has a weak point, such that the handle can be broken off from the blood plasma collection device.

48. A kit of parts comprising: a blood filter device according to any of articles 1-36, and a blood plasma collection device according to any of articles 42-47.

49. A blood filtration device comprising a housing, wherein a blood plasma separation configuration is arranged in the housing, the blood plasma configuration being configured to separate blood plasma from a blood sample and leading separated blood plasma to a channel (44), wherein the housing comprises a receptacle for receiving a blood plasma collecting device such that a collection end of the blood plasma collecting device is arranged at the channel (44). 50. The blood filtration device according to article 49, wherein a wiping material (26) is arranged in the receptacle, wherein the wiping material is arranged and configured to remove excess blood plasma from the blood plasma collecting device, when it is removed from the receptacle.

51. A blood filtration device according to article 49 or 50, wherein the blood filtration device includes any of the features as described in articles 1-36, and/or wherein the blood plasma collecting device includes any of the features as described in articles 42-47.

52. A blood filtration device comprising a housing, wherein a blood plasma separation configuration is arranged in the housing, the blood plasma configuration being configured to separate blood plasma from a blood sample, wherein a blood well (22) for collection of a blood sample is formed in the housing, wherein the blood well is arranged to communicate with the blood plasma filter (32), wherein the blood filtration device further comprises a lid, which is configured to provide a sealing connection to the housing so as to form a sealed volume at the blood well.

53. The blood filtration device according to article 52, wherein the lid and the blood well are configured to form a sealing connection in an interior part of the blood well, e.g. via a sealing lip or ring formed in the lid or in the interior of the blood well.

54. The blood filtration device according to article 52, wherein the housing comprises a protrusion, wherein the blood well is formed with the protrusion, and wherein the lid is configured to fit to an exterior part of the protrusion, such that the sealing connection is formed between an interior part of the lid and the exterior part of the protrusion, e.g. via a sealing lip or ring formed in the lid or at the exterior part of the protrusion.

55. The blood filtration device according to any of articles 52-54, wherein the lid comprises an interior pressure membrane that covers a top part of the lid.

56. The blood filtration device according to any of articles 52-55, wherein the lid is connected to a housing via a flap such that the lid can only be connected to the housing in a single manner. 57. A blood filtration device according to any of articles 52-56, wherein the blood filtration device includes any of the features as described in articles 1-36, and/or wherein the blood plasma collecting device includes any of the features as described in articles 42-47.

Items

1. A blood filtration device (10) comprising: a layered construction comprising a collection layer (40, 140) arranged between a first layer structure (30, 130) and a second layer structure (50, 150); wherein the collection layer (40, 140) comprises an aperture (42, 142) such that a collection volume (42', 142') is formed between the first layer structure (30, 130) and the second layer structure (50, 150), and wherein the collection layer (40, 140) further comprises a channel (44, 144) extending between the collection volume (42', 142') and a periphery (46, 146) of the collection layer (40, 140); wherein the first layer structure (30, 130) comprises a blood plasma filter (32, 132), which is arranged to communicate with the collection volume (42', 142'); and wherein the second layer structure (50, 150) comprises an air ventilation filter (52, 152) arranged to communicate with the collection volume (42', 142') and configured for removing gasses from the collection volume (42', 142⁷).

2. The blood filtration device according to item 1, wherein the first layer structure is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material.

3. The blood filtration device according to any of items 1-2, wherein the first layer structure comprises a number of separate parts, e.g. formed as a separate layers.

4. The blood filtration device according to items 3, wherein at least one of the separate parts of the first layer structure is made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

5. The blood filtration device according to any of items 3-4, wherein the first layer structure comprises a primary layer made of a flexible material, such as a flexible polymer material or an elastomeric material, an optional liner, and the blood plasma filter, optionally with a double-adhesive layer arranged between the primary layer and the liner.

6. The blood filtration device according to item 5, wherein the primary layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm, and/or wherein the double-adhesive layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

7. The blood filtration device according to any of items 1-6, wherein the second layer structure is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material.

8. The blood filtration device according to any of items 1-7, wherein the second layer structure comprises a number of separate parts, e.g. formed as separate layers.

9. The blood filtration device according to any of items 7-8, wherein at least one of the separate parts of the second layer structure are made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

10. The blood filtration device according to any of items 7-9, wherein the second layer structure comprises a primary layer made of a flexible material, e.g. a flexible polymer material or an elastomeric material, an optional liner, and the air ventilation filter, optionally with a double-adhesive layer arranged between the primary layer and the air ventilation filter, alternatively between the primary layer and the optional liner.

11. The blood filtration device according to any of item 10, wherein the primary layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm, and/or wherein the double-adhesive layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

12. The blood filtration device according to any of items 1-11, wherein the air ventilation filter is a semipermeable membrane, such as a hydrophobic membrane, that allows gasses to pass through the membrane but does not allow the blood component to pass through the membrane.

13. The blood filtration device according to any of items 1-12, wherein the blood plasma filter comprises a separation membrane and a spreading layer configured for spreading a blood sample to cover the separation membrane.

14. The blood filtration device according to any of items 1-13, wherein the blood plasma filter has a maximum outer dimension, such as a diameter, of 3-20 mm, preferably 5-18 mm, more preferably 8-15 mm, such as around 12mm.

15. The blood filtration device according to any of items 1-14, wherein the collection layer is at least partly made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

16. The blood filtration device according to item 15, wherein the collection layer is formed by a double-adhesive layer, such as a double-sided tape.

17. The blood filtration device according to any of items 1-16, wherein the collection layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

18. The blood filtration device according to any of items 1-17, wherein the aperture of the collection layer has a maximum inner dimension, such as a diameter, of 3-15 mm, preferably 4-12 mm, more preferably 5-10 mm.

19. The blood filtration device according to any of items 1-18, wherein the collection volume, when filled with blood plasma, has a volume of 5-15 ml.

20. The blood filtration device according to any of items 1-19, wherein the channel (44) in the connection layer (40) has a width of 0.1-2.0 mm, preferably 0.3-1.5 mm, more preferably 0.5-1.0 mm.

21. The blood filtration device according to any of items 1-20, wherein the blood filtration device further comprises a housing, and wherein the layered construction is arranged in the housing.

22. The blood filtration device according to item 21, wherein a blood well (22) for collection of a blood sample is formed in the housing, wherein the blood well is arranged to communicate with the blood plasma filter (32).

23. The blood filtration device according to any of items 21-22, wherein the housing comprises a receptacle for receiving a blood plasma collecting device such that a collection end of the blood plasma collecting device is arranged at the channel (44) of the collection layer (40).

24. The blood filtration device according to item 23, wherein a wiping material (26) is arranged in the receptacle, wherein the wiping material is arranged and configured to remove excess blood plasma from the blood plasma collecting device, when it is removed from the receptacle.

25. The blood filtration device according to any of items 22-24, wherein the blood filtration device further comprises a lid, which is configured to provide a sealing connection to the housing so as to form a sealed volume at the blood well.

26. The blood filtration device according to item 25, wherein the lid and the blood well are configured to form a sealing connection in an interior part of the blood well, e.g. via a sealing lip or ring formed in the lid or in the interior of the blood well.

27. The blood filtration device according to item 25, wherein the housing comprises a protrusion, wherein the blood well is formed with the protrusion, and wherein the lid is configured to fit to an exterior part of the protrusion such that the sealing connection is formed between an interior part of the lid and the exterior part of the protrusion, e.g. via a sealing lip or ring formed in the lid or at the exterior part of the protrusion.

28. The blood filtration device according to any of items 25-27, wherein the lid comprises an interior pressure membrane that covers a top part of the lid.

29. The blood filtration device according to any of items 25-28, wherein the lid is connected to a housing via a flap such that the lid can only be connected to the housing in a single manner.

30. A blood filtration and blood plasma collection system comprising a blood filtration device according to any of items 1-29, and a removable blood plasma collection device connected to the blood connection device.

31. The blood filtration and blood plasma collection system according to item 30 and at least item 23, wherein the blood plasma collection device is received in the receptacle of the blood filtration device.

32. The blood filtration and blood plasma collection system according to item 31, wherein the blood plasma collection device comprises a capillary tube, and wherein the blood plasma collection device is configured such that a first end of the capillary tube is arranged at the channel at the periphery of the collection layer, when the blood plasma collection device is positioned in the receptacle of the blood filtration device.

33. A blood plasma collection device comprising: a capillary tube comprising a first end for collecting blood plasma and a second end, a holder for holding the capillary tube, and a handle connected to the holder and arranged proximal to the second end of the capillary tube, e.g. wherein the blood plasma collection device is configured to be received in a receptacle of a blood filtration device according to any of items 1-29.

34. The blood plasma collection device according to item 33, wherein the holder is attached to an exterior portion of the capillary tube.

35. The blood plasma collection device according to any of items 33-34, wherein the holder comprises an exterior seal, such as a sealing ring, preferably arranged near the second end of the capillary tube.

36. The blood plasma collection device according to any of items 33-35, wherein the holder has a weak point, such that the handle can be broken off from the blood plasma collection device.

37. A kit of parts comprising: a blood filter device according to any of items 1-29, and a blood plasma collection device according to any of items 33-36.

38. A blood filtration device comprising a housing, wherein a blood plasma separation configuration is arranged in the housing, the blood plasma configuration being configured to separate blood plasma from a blood sample and leading separated blood plasma to a channel (44), wherein the housing comprises a receptacle for receiving a blood plasma collecting device such that a collection end of the blood plasma collecting device is arranged at the channel (44).

39. The blood filtration device according to item 38, wherein a wiping material (26) is arranged in the receptacle, wherein the wiping material is arranged and configured to remove excess blood plasma from the blood plasma collecting device, when it is removed from the receptacle.

40. A blood filtration device according to item 38 or 39, wherein the blood filtration device includes any of the features as described in items 1-29, and/or wherein the blood plasma collecting device includes any of the features as described in items 33-36.

41. A blood filtration device comprising a housing, wherein a blood plasma separation configuration is arranged in the housing, the blood plasma configuration being configured to separate blood plasma from a blood sample, wherein a blood well (22) for collection of a blood sample is formed in the housing, wherein the blood well is arranged to communicate with the blood plasma filter (32), wherein the blood filtration device further comprises a lid, which is configured to provide a sealing connection to the housing so as to form a sealed volume at the blood well.

42. The blood filtration device according to item 41, wherein the lid and the blood well are configured to form a sealing connection in an interior part of the blood well, e.g. via a sealing lip or ring formed in the lid or in the interior of the blood well.

43. The blood filtration device according to item 41, wherein the housing comprises a protrusion, wherein the blood well is formed with the protrusion, and wherein the lid is configured to fit to an exterior part of the protrusion, such that the sealing connection is formed between an interior part of the lid and the exterior part of the protrusion, e.g. via a sealing lip or ring formed in the lid or at the exterior part of the protrusion.

44. The blood filtration device according to any of items 41-43, wherein the lid comprises an interior pressure membrane that covers a top part of the lid. 45. The blood filtration device according to any of items 41-44, wherein the lid is connected to a housing via a flap such that the lid can only be connected to the housing in a single manner.

46. A blood filtration device according to any of items 41-45, wherein the blood filtration device includes any of the features as described in items 1-29, and/or wherein the blood plasma collecting device includes any of the features as described in items

List of reference numerals

10, 210 blood filtration device

212 layered construction

20, 220 housing

220', 220" housing parts

22, 222, 322 blood well

24 protrusion

26, 226 wiping material

227 support structure

229 blood indicator

30, 130 first layer structure

32, 132, 232 blood plasma filter

233 indication activation layer

34, 134 liner

235 blood collection indicator

36, 236 double-adhesive tape

38, 138, 238 flexible layer

40, 240 collection layer

42, 242 aperture

42' collection volume

44, 244 channel

46, 246 periphery

50, 150 second layer structure

52, 152 air ventilation filter / semipermeable membrane

54 double-adhesive tape

56, 156 flexible layer

60, 260, 360 lid 62 pressure membrane

64 sealing

66, 266 flap

70, 270, 370 blood plasma collecting device 72, 272, 372 capillary tube

73, 273, 373 first end of capillary tube

74, 274 holding arrangement

75, 275, 375 second end of capillary tube

76 sealing ring 78, 278 handle

279 snap lock

280, 380, 380 plasma sample indicator

282 auxiliary channel

Claims

2. The blood filtration device according to claim 1, wherein the second layer structure (50, 150) comprises an air ventilation filter (52, 152) arranged to communicate with the collection volume (42', 142') and configured for removing gasses from the collection volume (42', 142').

3. The blood filtration device according to any of claims 1-2, wherein the collection volume and the channel are formed in a single collection layer.

4. The blood filtration device according to any of claims 1-2, wherein the collection volume and the channel are formed in separate layers of the collection layer structure.

5. The blood filtration device according to any of claims 1-4, wherein the first layer structure is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material.

6. The blood filtration device according to any of claims 1-5, wherein the first layer structure comprises a number of separate parts, e.g. formed as a separate layers.

7. The blood filtration device according to claim 6, wherein at least one of the separate parts of the first layer structure is made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

8. The blood filtration device according to any of claims 6-7, wherein the first layer structure comprises a primary layer made of a flexible material, such as a flexible polymer material or an elastomeric material, an optional liner, and the blood plasma filter, optionally with a double-adhesive layer arranged between the primary layer and the liner.

9. The blood filtration device according to claim 8, wherein the primary layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm, and/or wherein the double-adhesive layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

10. The blood filtration device according to any of claims 1-9, wherein the second layer structure is at least partly made of a flexible material, such as a flexible polymer or an elastomeric material.

11. The blood filtration device according to any of claims 1-10, wherein the second layer structure comprises a number of separate parts, e.g. formed as separate layers.

12. The blood filtration device according to any of claims 10-11, wherein at least one of the separate parts of the second layer structure are made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

13. The blood filtration device according to any of claims 10-12, wherein the second layer structure comprises a primary layer made of a flexible material, e.g. a flexible polymer material or an elastomeric material, an optional liner, and optionally the air ventilation filter, optionally with a double-adhesive layer arranged between the primary layer and the air ventilation filter, alternatively between the primary layer and the optional liner.

14. The blood filtration device according to claim 13, wherein the primary layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.3-0.15 mm, e.g. around 0.05 mm, and/or wherein the double-adhesive layer has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

15. The blood filtration device according to any of claims 1-14, wherein the air ventilation filter is a semipermeable membrane, such as a hydrophobic membrane, that allows gasses to pass through the membrane but does not allow the blood component to pass through the membrane.

16. The blood filtration device according to any of claims 1-15, wherein the blood plasma filter comprises a separation membrane and a spreading layer configured for spreading a blood sample to cover the separation membrane.

17. The blood filtration device according to any of claims 1-16, wherein the blood plasma filter has a maximum outer dimension, such as a diameter, of 3-20 mm, preferably 5-18 mm, more preferably 8-15 mm, such as around 12mm.

18. The blood filtration device according to any of claims 1-17, wherein the collection layer or collection layer structure is at least partly made of a flexible material, e.g. a flexible polymer material or an elastomeric material, such as polyethylene or polyethylene terephthalate.

19. The blood filtration device according to claim 18, wherein the collection layer or collection layer structure is formed by a double-adhesive layer, such as a double-sided tape.

20. The blood filtration device according to any of claims 1-19, wherein the collection layer or collection layer structure has a thickness of 0.01-0.3 mm, preferably 0.02-0.2 mm, more preferably 0.5-0.15 mm, e.g. around 0.10 mm.

21. The blood filtration device according to any of claims 1-20, wherein the aperture of the collection layer or collection layer structure has a maximum inner dimension, such as a diameter, of 3-15 mm, preferably 4-12 mm, more preferably 5-10 mm.

22. The blood filtration device according to any of claims 1-21, wherein the collection volume, when filled with blood plasma, has a volume of 5-15 ml.

23. The blood filtration device according to any of claims 1-20, wherein the collection layer or collection layer structure has a maximum inner dimension, such as a diameter, of 0.1-5 mm, preferably 0.3-4 mm, more preferably 0.5-3 mm.

24. The blood filtration device according to claim 23, wherein the collection volume, when filled with blood plasma, has a volume of 0.1-2 ml, e.g. around 1 ml.

25. The blood filtration device according to any of claims 1-24, wherein the channel (44) in the connection layer (40) has a width of 0.1-2.0 mm, preferably

0.3-1.5 mm, more preferably 0.5-1.0 mm.

26. The blood filtration device according to any of claims 1-25, wherein the blood filtration device further comprises a housing, and wherein the layered construction is arranged in the housing.

27. The blood filtration device according to claim 26, wherein a blood well (22) for collection of a blood sample is formed in the housing, wherein the blood well is arranged to communicate with the blood plasma filter (32).

28. The blood filtration device according to any of claims 26-27, wherein the housing comprises a receptacle for receiving a blood plasma collecting device such that a collection end of the blood plasma collecting device is arranged at the channel (44) of the collection layer or collection layer structure (40).

29. The blood filtration device according to claim 28, wherein a wiping material (26) is arranged in the receptacle, wherein the wiping material is arranged and configured to remove excess blood plasma from the blood plasma collecting device, when it is removed from the receptacle.

30. The blood filtration device according to any of claims 27-29, wherein the blood filtration device further comprises a lid, which is configured to provide a sealing connection to the housing so as to form a sealed volume at the blood well.

31. The blood filtration device according to claim 30, wherein the lid and the blood well are configured to form a sealing connection in an interior part of the blood well, e.g. via a sealing lip or ring formed in the lid or in the interior of the blood well.

32. The blood filtration device according to claim 30, wherein the housing comprises a protrusion, wherein the blood well is formed with the protrusion, and wherein the lid is configured to fit to an exterior part of the protrusion such that the sealing connection is formed between an interior part of the lid and the exterior part of the protrusion, e.g. via a sealing lip or ring formed in the lid or at the exterior part of the protrusion.

33. The blood filtration device according to any of claims 30-32, wherein the lid comprises an interior pressure membrane that covers a top part of the lid.

34. The blood filtration device according to any of claims 30-33, wherein the lid is connected to a housing via a flap such that the lid can only be connected to the housing in a single manner.

35. The blood filtration device according to any of claims 1-34, wherein the blood filtration device comprises a blood indicator, which is arranged to communicate with the blood plasma filter and is configured to indicate when the blood plasma filter has been saturated with a blood sample.

36. The blood filtration device according to any of claims 1-35, wherein the blood filtration device further comprises a plasma sample indicator arranged and configured to indicate when a collection volume, e.g. a capillary tube, of the blood plasma collection device has been filled.

37. A blood filtration and blood plasma collection system comprising a blood filtration device according to any of claims 1-36, and a removable blood plasma collection device connected to the blood connection device.

38. The blood filtration and blood plasma collection system according to claim 37, wherein the blood plasma collection device is received in the receptacle of the blood filtration device.

39. The blood filtration and blood plasma collection system according to claim 38, wherein the blood plasma collection device comprises a capillary tube, and wherein the blood plasma collection device is configured such that a first end of the capillary tube is arranged at the channel at the periphery of the collection layer or collection layer structure, when the blood plasma collection device is positioned in the receptacle of the blood filtration device.

40. The blood filtration and blood plasma collection system according to claim 39, wherein the plasma sample indicator is arranged to communicate with a second end of the capillary tube, e.g. arranged in direct contact with the second end of the capillary tube or connected via a channel.

41. The blood filtration and blood plasma collection system according to claim 40, wherein the plasma sample indicator is arranged to communicate with an auxiliary channel, wherein the auxiliary channel has an end arranged at the channel at the periphery of the collection layer or collection layer structure.

42. A blood plasma collection device comprising: a capillary tube comprising a first end for collecting blood plasma and a second end, a holder for holding the capillary tube, and preferably a handle connected to the holder, e.g. wherein the blood plasma collection device is configured to be received in a receptacle of a blood filtration device according to any of claims 1-36.

43. The blood plasma collection device according to claim 42, wherein the holder is attached to an exterior portion of the capillary tube.

44. The blood plasma collection device according to any of claims 42-43, wherein the handle is arranged proximal to the second end of the capillary tube.

45. The blood plasma collection device according to any of claims 42-44, wherein the holder and optional handle are oriented in a direction that is substantially orthogonal to an orientation of the capillary tube.

46. The blood plasma collection device according to any of claims 42-45, wherein the holder comprises an exterior seal, such as a sealing ring, preferably arranged near the handle, e.g. at the second end of the capillary tube.

47. The blood plasma collection device according to any of claims 42-46, wherein the holder has a weak point, such that the handle can be broken off from the blood plasma collection device.

48. A kit of parts comprising: a blood filter device according to any of claims 1-36, and a blood plasma collection device according to any of claims 42-47.

49. A blood filtration device comprising a housing, wherein a blood plasma separation configuration is arranged in the housing, the blood plasma configuration being configured to separate blood plasma from a blood sample and leading separated blood plasma to a channel (44), wherein the housing comprises a receptacle for receiving a blood plasma collecting device such that a collection end of the blood plasma collecting device is arranged at the channel (44).

50. The blood filtration device according to claim 49, wherein a wiping material (26) is arranged in the receptacle, wherein the wiping material is arranged and configured to remove excess blood plasma from the blood plasma collecting device, when it is removed from the receptacle.

51. A blood filtration device according to claim 49 or 50, wherein the blood filtration device includes any of the features as described in claims 1-36, and/or wherein the blood plasma collecting device includes any of the features as described in claims 42-47.

53. The blood filtration device according to claim 52, wherein the lid and the blood well are configured to form a sealing connection in an interior part of the blood well, e.g. via a sealing lip or ring formed in the lid or in the interior of the blood well.

54. The blood filtration device according to claim 52, wherein the housing comprises a protrusion, wherein the blood well is formed with the protrusion, and wherein the lid is configured to fit to an exterior part of the protrusion, such that the sealing connection is formed between an interior part of the lid and the exterior part of the protrusion, e.g. via a sealing lip or ring formed in the lid or at the exterior part of the protrusion.

55. The blood filtration device according to any of claims 52-54, wherein the lid comprises an interior pressure membrane that covers a top part of the lid.

56. The blood filtration device according to any of claims 52-55, wherein the lid is connected to a housing via a flap such that the lid can only be connected to the housing in a single manner.

57. A blood filtration device according to any of claims 52-56, wherein the blood filtration device includes any of the features as described in claims 1-36, and/or wherein the blood plasma collecting device includes any of the features as described in claims