WO1998033597A1

WO1998033597A1 - Method and means for separating blood

Info

Publication number: WO1998033597A1
Application number: PCT/AU1998/000055
Authority: WO
Inventors: Maxwell Edmund Whisson
Original assignee: Australian Red Cross Society (Western Australian Division)
Priority date: 1997-01-31
Filing date: 1998-01-30
Publication date: 1998-08-06
Also published as: AUPO488697A0

Abstract

A storage reservoir (10) for blood comprising: a flexible walled first chamber (A) having an inlet (11) adapted to receive blood, said flexible walled first chamber (A) having one end, a closed flexible walled second chamber (B) intended to accommodate a solution, said second chamber (B) opening into the one end of the first chamber (A) through a flow control means (14) which is capable of being opened to allow the flow of the solution from the second chamber (B) to the first chamber (A); said reservoir (10) being adapted to be located in a centifuge whereby the one end is radially outermost during centrifugation; said reservoir (10) being adapted to cause the delivery of the solution into the first chamber (A) through the flow control means (14) as a result of forces induced by the centrifugation. Also a method of separation of blood components from blood using this structure, wherein the solution has nutrient and preservative qualities appropriate to the blood component remaining at the one end and wherein the density of the solution is less than the density of red cells.

Description

TITLE: Method and Means for Separating Blood

THIS INVENTION relates to a method for the separation of blood into its components.

Throughout the specification the term "blood" is to be taken as including whole blood and any mixture of blood components which may have been derived from a partial separation of whole blood or the like.

It is necessary at times to be able to separate blood into its various components in order to be able to provide concentrated red cells, concentrated platelets and plasma. Separation of blood into the above components is generally effected by centrifugation which can be effective in separating the red cells and platelets from the plasma. A difficulty arises however, in being able to discriminate between the red cells, the white cells and the platelets. While the red cells and platelets have a different density and sedimentation rate which can facilitate their separation by means of centrifugation, the difference is not great. Furthermore, the geometry of the two components does not facilitate their separation since both components have a flat configuration with a large surface area to mass ratio. In addition while the white blood ceils have a lower density than red cells they tend to sediment at a similar speed because of their smaller surface area to mass ratio. Therefore, when blood is separated by centrifugation, there is often only a partial separation of components since the layer of concentrated red blood cells retains a significant proportion of the platelets. Furthermore, conditions of centrifugation which are most effective in separating platelets may leave substantial amounts of valuable plasma trapped in the red cell layer, with white blood cells distributed through all layers.

In addition, red cells and platelets require different preservative solutions. Traditionally the primary anticoagulant which is utilised in the collection of blood is optimised to the needs of the red cells and it is not generally appropriate to the needs of the platelets or to the maintenance of the plasma in the native state. In addition, a preservative solution which is appropriate for platelets can be detrimental to the red cells.

It is therefore desirable that the separation of blood into red cells and platelets be enhanced and that once separation has been effected, an appropriate nutrient preservative solution can then be utilised for the red cells and the platelets respectively. Similarly, in certain circumstances it is desirable to separate and maintain white blood cells, for example neutrophils, lymphocytes or progenitor (stem) cells in appropriate preservative solutions. In addition it is also frequently desirable to be able to have the red blood cells or platelets or plasma relatively free of white blood cells.

In the past various means and methods have been used for separating blood components during centrifugation. These means generally involve pumping or delivering a saline solution into the concentrated cells collected by the centrifugation at the outer end and causing it to pass through the concentrated cells in order to effect some separation. This process is generally known as "elutriation" and has been effected using a complex array of chambers which has involved modification of existing centrifugation means and has required some external means in order to effect delivery of the saline solution.

Another method of elutriation has been disclosed in US patent specifications 4,262,718, 4,268,393 and 4,322,298 which disclose an arrangement where an elutriating fluid is delivered into a centrifuged blood sample while being centrifuged to effect the separation of platelet rich plasma from whole blood. The method of this prior art involves the use of a piston or like means which is caused under centrifugation to cause the collapse of a reservoir containing the elutriating fluid to positively displace or pump the fluid directly into the blood sample. In addition it is a characteristic of the prior art that the blood sample is accommodated in a specially designed receptacle having the configuration of an inverted cone whereby elutriating fluid is introduced into the blood sample from the bottom of the receptacle which is the apex of the cone and as a result the pathway for the elutriating fluid and the entrained platelets is maximised which results in an inefficiency in separation. In addition it has been found that moving pistons or weights bearing on flexible bag-like structures can have destructive effects under centrifugation.

It is an object of this invention to utilise a unitary structure which can be used in a substantially conventional centrifuge to effect a separation of cell components without modification of the centrifuge.

It is also an object of the invention that the density of the elutriating fluid is such that under centrifugation it is caused to move through the sedimented red blood cells as a result of the centripetal forces created by centrifugation rather than be caused to be positively displaced or pumped through the blood sample.

It is also an object of this invention to provide a method and means for improving the yield of the various blood components in the separation of blood by centrifugation.

It is also an object to provide a method of enriching the separated cells with appropriate nutrient and preservative solutions during the separations of cell components.

Accordingly the invention resides in a method of separation of blood components from blood, said blood being accommodated in a flexible walled reservoir comprising a first chamber and a flexible walled closed second chamber which is intended to contain a solution, wherein the second chamber communicates with the first chamber through a flow control means opening into one end of the first chamber, said method comprising subjecting the reservoir to centrifugation where the one end is radially outermost, opening the flow control means and causing the solution to be delivered into the one end of the first chamber through the flow control means by forces induced during the centrifugation, wherein the solution has nutrient and preservative qualities appropriate to the blood component remaining at the one end, where the density of the solution is preferably chosen to be less that the density of red cells so that at high radial gravitational forces, the solution tends to move centripetally with respect to the outwardly moving red cells.

As a result of the centripetal movement of the solution through the sedimented red blood cells it will tend to carry plasma and platelets through the red cells. The centripetal path for the solution need not be direct from the second chamber to the first chamber but may in fact involve one or more loops in which the fluid may be caused to move in a direction away from the centre of rotation for a part of its movement, however the overall movement of the fluid will be towards the centre of rotation.

According to a preferred feature of the embodiment the delivery of the solution to the first chamber is effected by the collapse of the second chamber during centrifugation by forces induced by the centrifugation.

According to a preferred feature of the invention, the delivery of solution from the second chamber into the first chamber is substantially evenly distributed over a significant proportion of the area of the one end of the first chamber.

According to a further preferred feature of the invention, the opening of the flow control means occurs prior to centrifugation.

According to an alternative preferred feature, the opening of the flow control means occurs as a result of centrifugation.

Accordingly, the invention also resides in a storage reservoir for blood comprising; a flexible walled first chamber having an inlet adapted to receive blood, said flexible walled first chamber having one end, a closed flexible walled second chamber intended to accommodate a solution, said second chamber opening into the one end of the first chamber through a flow control means which is capable of being opened to allow the flow of the solution from the second chamber to the first chamber; said reservoir being adapted to be located in a centrifuge whereby the one end is radially outermost during centrifugation; said reservoir being adapted to cause the delivery of the solution into the first chamber through the flow control means as a result of forces induced by the centrifugation.

According to a preferred feature of the invention the reservoir is adapted such that the flow of solution to the first reservoir is effected by the collapse of the second chamber as a result of the forces induced during centrifugation.

According to a preferred feature the second chamber is positioned to maximise the centripetal flow of solution into the first chamber under centrifugation.

According to a further preferred feature the flow control means is configured to limit the flow of blood products from the first chamber to the second chamber.

According to a preferred feature of the invention, the second chamber is accommodated within the walls of the first chamber. According to a further preferred feature the second chamber is located at the one end of the first chamber. According to a further preferred feature of the previous feature, the flow control means comprises one or more zones of weakness in the wall of the second chamber which can be ruptured to effect communication between the second and first chamber. The zones of weakness may be adapted to be such that they can be mechanically ruptured prior to centrifugation. Alternatively the zones of weakness may be capable of being ruptured upon the pressure within the second reservoir increasing beyond a predetermined range during centrifugation. According to an alternative preferred feature, the control means may comprise one or more openings provided in the wall of the second chamber which are each provided with a closure. According to a further preferred feature, the closure may be capable of being mechanically manipulated to be dislodged from the opening prior to centrifugation. According to a further preferred feature of the previous feature, the closure may be capable of being dislodged from the opening on the creation of inertia) forces during centrifugation.

According to a further preferred feature of the invention, the second chamber may be located to the exterior of the first chamber and communicates with the first chamber through a delivery passageway having an outlet located within the first chamber at the one end where said outlet is associated with said flow control means. According to one embodiment the reservoir may include a solid or fluid mass which on centrifugation will bear on the second chamber to cause its collapse.

According to a further preferred feature of the invention the flow control means includes a filter means which will control the flow of blood components from the first chamber through the flow control means on opening of the flow control means. According to one embodiment the filter means comprises a porous element formed with a plurality of small openings. According to one embodiment the filter means comprises a porous element formed from a matted fibrous material.

According to a further preferred feature of the invention the flow control means is associated with a manifold into which the solution is transferred from the second chamber. According to one embodiment the manifold has a volume sufficient to receive at least a portion of the solution in the second chamber.

The invention will be more fully understood in the light of the following description of several specific embodiment. The description will be made with reference to the accompanying drawings of which:

Figure 1 is a schematic side elevation of a storage reservoir according to the first embodiment;

Figures 2a and 2b are schematic side elevations of the first embodiment illustrating the flow control means;

Figures 3a and 3b are schematic side elevations of a second embodiment of the invention illustrating another form of flow control means;

Figure 4 is a side sectional elevation of a third embodiment of the invention; Figure 5 is a front elevation of the storage reservoir according to the third embodiment of Figure 4;

Figure 6 is a schematic side elevation of a fourth embodiment of the invention; and

Figure 7 is schematic illustration of a fifth embodiment of the invention.

Each of the embodiments illustrated in the accompanying drawings relate to a storage reservoir which is to be utilised initially for the storage of blood and in which the components of the blood can be separated by centrifugation. Subsequent to centrifugation, the respective components of the blood can be extracted by transferring one or more of the components into other storage reservoirs.

The first embodiment comprises a primary storage reservoir 10 which is of generally conventional form having the appropriate delivery line 11. The reservoir 10 is adapted to be able to be mounted into a centrifuge such that the one end 12 would be radially outermost during centrifugation.

The interior of the reservoir 10 is subdivided into a first chamber A which is generally defined by the external walls of the reservoir 10 and a second chamber B which is located at the one end 12 of the first chamber A and is defined by an intermediate wall provided across the internal space of the reservoir 10 towards the one end 12. The second chamber B contains a preservative nutrient solution having a density less than the red cells. This solution can be introduced during manufacture of the bag or alternatively may be introduced prior to collection of blood or alternatively prior to centrifugation. Introduction of the solution into the second chamber B may be effected by an additional delivery line (not shown) which passes through the other end of the reservoir 10.

The intermediate wall 13 is formed with a plurality of zones 14 which are designed to be capable of being opened. The zones can comprise zones of reduced thickness which can be ruptured by the application of moderately increased fluid pressure to the contents of the second reservoir. Alternatively the zones may be provided by adhering the opposed walls of the reservoir together along a line and providing locations where the adhesion between the walls can be overcome by the application of moderately increased pressure to the contents of the second reservoir.

The first chamber A contains a primary anticoagulant which is of a bland unspecialised form and which would not be significantly detrimental to either plasma, plateiets or red cells and which will inhibit undesirable responses of the blood to the collection environment.

In use, the blood is collected in the reservoir 10 by being delivered into the first chamber A. When filled, the delivery lines are closed off in the conventional manner and the reservoir 10 is prepared for centrifugation. Prior to centrifugation, the flow control means in the form of the zones of weakness 14 in the intermediate wall 13 are ruptured by a mechanical manipulation of the reservoir 10 such that a flow can be induced between the first and second reservoirs.

On centrifugation, the red cells together with a significant proportion of platelets are carried to the one end of the reservoir 10 such that they lie against the intermediate wall 13 and the medium above the red cells comprises a mixture of platelets, white blood cells and plasma with the greater predominance of white blood cells and platelets lying adjacent the upper surface of the red cells.

As a result of the density differential between the elutriating fluid and the red blood cells and/or the pressure which is induced upon the second chamber B during centrifugation, the preservative solution which is contained within the second reservoir B is caused to flow through the intermediate wall 13 into the first reservoir A and mix with the concentrated red cells in the region of the one end. The introduction of the preservative solution into the concentrated red cells and passage of that solution through the concentrated red cells serves to facilitate the movement of the platelets and trapped plasma through the concentrated red cells to the surface of the layer of red cells. At the conclusion of centrifugation, the second chamber B would have been substantially emptied, with its contents being delivered into the first reservoir to lie substantially within the layer of concentrated red cells. In addition a significant proportion of the platelets which would have been otherwise retained within the layer of the red cells will have moved into the plasma overlying the red cells.

The platelet rich plasma can then be transferred from the reservoir 10 into a further reservoir by conventional means whereby the platelets can be extracted from the plasma by further centrifugation. This can be done in a similar manner as described above utilising a reservoir according to the embodiment in order that the concentration of the residual white blood cells in the platelets can be reduced and in order that a preservation solution favourable to platelets can be introduced into the platelet pellet resulting from centrifugation. The plasma overlying the layer of platelets so produced can then be further transferred into a third reservoir for storage of the plasma. In this case the second reservoir prior to the introduction of the platelet containing plasma may be provided with a preservative solution which is appropriate for platelets, while the third reservoir may be provided with a preservative solution which is appropriate for the plasma.

As a result of the embodiment, the separation of platelets and red cells is enhanced to improve the yield of platelets compared to the yield by conventional extraction methods. Furthermore, the embodiment comprises utilisation of specialised preservative solutions appropriate to each of the components being extracted. The invention also provides a means of adding a preservative solution to the red cell layer during the formation of that layer so that the usual manual method of adding the preservative solution may not be required.

Figures 2a and 2b schematically illustrate the rupturing of the zones of weakness 14 which provide the flow control means between the second reservoir B and the first reservoir A.

According to a variation of the first embodiment the intermediate wall may be associated with a porous layer which serves as a filter to prevent the transfer of the red blood cells into the second chamber. Figures 3a and 3b illustrate a second embodiment of the invention which is a variation from the first embodiment in relation to the nature of the flow control means only. The flow control means of the second embodiment comprises the provision of a plurality of openings 14 through the intermediate wall 13 which are closed by closures in the form of plugs 15. The plugs 15 are located in the openings 14 such that they can be dislodged into the second reservoir B and are incapable of being dislodged into the first chamber A. In addition, the plugs 15 are formed such that under centrifugation, the plugs will be subjected to significant inertial forces and will be dislodged from the openings 14.

According to a variation of the second embodiment the intermediate wall may be associated with a porous layer which serves as a filter to prevent the transfer of the red blood cells into the second chamber.

The third embodiment which is shown at Figures 4 and 5 comprises a reservoir 110 where the second chamber B is located at the other end of the reservoir 110 and is provided with a delivery tube 116 which opens into the first chamber A at the one end 112 through a suitable outlet manifold 117 to enable a substantially even distribution of the preservative solution into the first chamber A across the one end 112 of that chamber. It is anticipated that under centrifugation, the inertial forces exerted upon the solution within the second chamber B will cause delivery of the solution into the first chamber A through the manifold 1 17. The flow control means may comprise any suitable means for selectively opening the delivery line 116 prior to mounting of the reservoir 110 within the centrifuge. According to another form of the embodiment the second chamber B may be modified such that under centrifugation the second chamber B is caused to positively collapse. Such modification may comprise incorporation of a mass into the reservoir at the end wall of the second chamber B which would be radially innermost during centrifugation and which by virtue of the inertial forces exerted on it during centrifugation will cause the collapse of the second chamber B to provide for a controlled delivery of solution into the first chamber A. According to a variation of the previous embodiment the mass may comprise a flexible closed chamber which surrounds the second chamber B and which _is filled with a high density liquid such as a concentrated saline solution. The arrangement is such that under centrifugation the second chamber B is located innermost with respect to the closed chamber and the forces which are induced on the high density liquid will cause the second chamber B to collapse and deliver the preservative solution to the first chamber A.

In addition a further alternative means of using the third embodiment is to squeeze the second chamber manually prior to centrifugation to deliver the preservative solution to the manifold whereby under centrifugation the solution is delivered into the first chamber. This will require that the manifold has sufficient volume to be able to accommodate the solution between the solution being delivered from the second chamber and prior to centrifugation. In addition the flow control means in the manifold can be one where it is opened manually prior to centrifugation or as a result of the forces induced during centrifugation as described in relation to previous embodiments.

According to a further variation of the third embodiment of Figures 4 and 5 the manifold may 117 may incorporate a porous layer formed of a matted fibrous material which serves as a filter to prevent the transfer of the red blood cells into the manifold and second chamber.

Figure 6 illustrates a fourth embodiment of the invention which is generally similar to the first embodiment except for the flow control means. The fifth embodiment provides a primary storage reservoir 310 which is also of a generally conventional form having the appropriate delivery line 311. The reservoir 310 is adapted to be able to be mounted into a centrifuge such that the one end 312 will be radially outermost during centrifugation. The reservoir according to the embodiment is formed from two sheets of plastic sheet material or alternatively a single folded sheet which are welded around the outer perimeter and provide the enclosed reservoir 310. In addition the interior of the reservoir 310 is divided into two sub-chambers A and B by an intermediate weld line 313 which extends from the top of the reservoir 310 downwardly in parallel relation to one side of the reservoir to a position spaced from the bottom and which then extends laterally across the reservoir 310. The lateral portion 313A of the partition is formed with a plurality of apertures or alternatively may be formed of a filter medium such as a matted fibrous material.

A further partition 318 is formed to the side of the first partition 313 remote from the first chamber A. The further partition 318 is co-extensive with the first partition 313 except for the junction 320 between the upper end of the further partition 318 and the top edge of the reservoir 310. The further partition 318 serves to provide a convoluted flow path for the contents of the second chamber B in their passage to the first chamber A whereby these contents are required to pass upwardly between the side wall of the chamber 310 and the further partition 318 and then downwardly between the first partition 313 and the further partition 318 until they are able to flow into the interior of the first chamber A through the lateral portion 313A of the first partition 313.

The junction portion 320 of the further partition 318 is formed with a closure which may be capable of being ruptured manually or opened manually for example by removal of an external clip or alternatively is capable of being ruptured as a result of the exertion of centrifugal forces on the reservoir 318. As in the case of the first embodiment, on the closure 320 being opened and the reservoir 310 being subjected to centrifugation the fluid from the second reservoir B is caused to flow into the first reservoir A by passage through the convoluted passageway provided by the further partition 318 and through the apertures 314 into the first chamber A.

It is believed that the fourth embodiment provides a means of resisting movement of the concentrated red blood cells into the second chamber B against the flow of preservative solution which is being forced into the first chamber A.

In a further embodiment which is a variant of the fourth embodiment the convoluted flow path may be opened as a result of centrifugation. It should be appreciated that each of the embodiments referred to above can also be used in separation of the platelets from white blood cells and from the plasma subsequent to separation of the red blood cells.

The fifth embodiment shown at Figure 7 comprises a variation of the first embodiment in which the second chamber B comprises a separate bag connected to chamber A which also comprises a bag connected by a flexible tube 414 which comprises the flow control means. The portion of the tube 414 contained within chamber B has a plurality of holes allowing the flow of elutriating fluid into the blood components in A over a wide area. The second chamber B contains a preservative nutrient solution with a density less than that of the red blood cell suspended in an anticoagulant fluid which is contained in chamber A having been collected according to conventional blood collection methods. As supplied, and during blood collection, a closure in the tube 414 prevents the flow of nutrient solution from B to A and anticoagulant solution or blood from A to B. The closure may be a conventional external clamp which compresses the connecting tube and which can be easily removed by the operator immediately before placing both bags in a centrifuge bucket. During centrifugation the net movement of the less dense fluid in B will tend to be centripetally directed. Thus the elutriating nutrient preservative solution is expected to flow from B to A during centrifugation and it will further tend to move centripetally through the blood or other particulate suspension in A so tending to carry suspending plasma and particles with slow sedimentation rate properties centripetally and free of the high sedimentation rate particles such as red blood cells.

A difficulty which may occur is that anticoagulated blood may, under certain conditions, tend to flow from A to B, at least into the outer portion of the bag when centrifuged. In order to overcome this possibility a further variation of the tube 414 connecting B to A may be filled entirely or for part of its length (especially the part in A) with a matted or porous or fibrous material the effect of which is to resist the passage of particulate matter such as red blood cells. As an alternative the plurality of holes in the tube within the chamber A may be loosely covered with flexible plastic flap valves the action of which is to close off the holes when pressed down onto the tube but to allow free movement of fluid from B, along the tube, through the holes and into A.

In each of the above embodiments, suitable connecting ports and connecting tubes may be incorporated to facilitate the aseptic transfer of fluids and components to and from the chamber. In addition the chamber may incorporate appropriate connecting tubes with manually operable closures of the form currently available with blood collection sets. In addition the chambers may be connected to other chambers or bags to facilitate the transfer of separated blood fractions into separate containers in which the separated blood fractions may be stored or subject to further fractionation or from which the separated blood fractions may be transfused to a patient for therapeutic purposes

Throughout this specification (including the claims if present), unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

It should be appreciated that the scope of the present invention need not be limited to the particular scope of the embodiment described above.

Claims

The Claims defining the invention are as follows:-

1. A method of separation of blood components from blood, said blood being accommodated in a flexible walled reservoir comprising a first chamber and a flexible walled closed second chamber which is intended to contain a solution, wherein the second chamber communicates with the first chamber through a flow control means opening into one end of the first chamber, said method comprising subjecting the reservoir to centrifugation where the one end is radially outermost, opening the flow control means and causing the solution to be delivered into the one end of the first chamber through the flow control means by forces induced during the centrifugation, wherein the solution has nutrient and preservative qualities appropriate to the blood component remaining at the one end wherein, the density of the solution is less that the density of red cells.

2. A method of separation of blood components from blood as claimed at claim 1 wherein the delivery of the solution to the first chamber is effected by the collapse of the second chamber during centrifugation by forces induced by the centrifugation.

3. A method of separation of blood components from blood as claimed at claim 1 or 2 wherein the delivery of solution from the second chamber into the first chamber is substantially evenly distributed over a significant proportion of the area of the one end of the first chamber.

4. A method of separation of blood components from blood as claimed at any one of the preceding claims wherein, the opening of the flow control means occurs prior to centrifugation.

5. A method of separation of blood components from blood as claimed at any one of claims 1 to wherein, the opening of the flow control means occurs as a result of centrifugation.

6. A method of separation of blood components from blood substantially as herein described

7. A storage reservoir for blood comprising; a flexible walled first chamber having an inlet adapted to receive blood, said flexible walled first chamber having one end, a closed flexible walled second chamber intended to accommodate a solution, said second chamber opening into the one end of the first chamber through a flow control means which is capable of being opened to allow the flow of the solution from the second chamber to the first chamber; said reservoir being adapted to be located in a centrifuge whereby the one end is radially outermost during centrifugation; said reservoir being adapted to cause the delivery of the solution into the first chamber through the flow control means as a result of forces induced by the centrifugation.

8. A storage reservoir for blood as claimed at claim 7 wherein the reservoir is adapted such that the flow of solution to the first reservoir is effected by the collapse of the second chamber as a result of the forces induced during centrifugation.

9. A storage reservoir for blood as claimed at claim 7 or 8 wherein the second chamber is positioned to maximise the centripetal flow of solution into the first chamber under centrifugation.

10. A storage reservoir for blood as claimed at claim 7 or 8 or 9 wherein the flow control means is configured to limit the flow of blood products from the first chamber to the second chamber.

1 1. A storage reservoir for blood as claimed at any one of claims 7 to 10 wherein, the second chamber is accommodated within the walls of the first chamber.

12. A storage reservoir for blood as claimed at any one of claims 7 to 11 wherein the second chamber is located at the one end of the first chamber.

13. A storage reservoir for blood as claimed at any one of claims 7 to 12 wherein, the flow control means comprises one or more zones of weakness in the wall of the second chamber which can be ruptured to effect communication between the second and first chamber.

14. A storage reservoir for blood as claimed at claim 13 wherein the zones of weakness may be adapted to be such that they can be mechanically ruptured prior to centrifugation.

15. A storage reservoir for blood as claimed at claim 13 wherein the zones of weakness may be capable of being ruptured upon the pressure within the second reservoir increasing beyond a predetermined range during centrifugation.

16. A storage reservoir for blood as claimed at any one of claims 7 to 12 wherein, the flow control means comprises one or more openings provided in the wall of the second chamber which are each provided with a closure.

17. A storage reservoir for blood as claimed at claim 16 wherein the closure may be capable of being mechanically manipulated to be dislodged from the opening prior to centrifugation.

18. A storage reservoir for blood as claimed at claim 16, wherein the closure may be capable of being dislodged from the opening on the creation of inertial forces during centrifugation.

19. A storage reservoir for blood as claimed at any one of claims 7 to 10 wherein, the second chamber is be located to the exterior of the first chamber and communicates with the first chamber through a delivery passageway having an outlet located within the first chamber at the one end where said outlet is associated with said flow control means.

20. A storage reservoir for blood as claimed at claim 19 wherein, the reservoir includes include a mass which on centrifugation will bear on the second chamber to cause its collapse.

21. A storage reservoir for blood as claimed at claim 20 wherein the mass comprises a solid mass.

22. A storage reservoir for blood as claimed at claim 20 wherein the mass comprises a fluid mass.

23. A storage reservoir for blood as claimed at any one of claims 19 to 22 wherein the flow control means is associated with a manifold into which the solution is transferred from the second chamber.

24. A storage reservoir for blood as claimed at claim 23 wherein the manifold has a volume sufficient to receive at least a portion of the solution in the second chamber.

25. A storage reservoir for blood as claimed at any one of claims 19 to 24 wherein, the flow control means comprises one or more zones which can be ruptured to effect communication between the second and first chamber.

26. A storage reservoir for blood as claimed at claim 25 wherein the zones of weakness may be adapted to be such that they can be mechanically ruptured prior to centrifugation.

27. A storage reservoir for blood as claimed at claim 26 wherein the zones of weakness may be capable of being ruptured upon the pressure within the second reservoir increasing beyond a predetermined range during centrifugation.

28. A storage reservoir for blood as claimed at any one of claims 19 to 24 wherein, the flow control means comprises one or more openings which are each provided with a closure.

29. A storage reservoir for blood as claimed at claim 28 wherein the closure may be capable of being mechanically manipulated to be dislodged from the opening prior to centrifugation.

30. A storage reservoir for blood as claimed at claim 28, wherein the closure may be capable of being dislodged from the opening on the creation of inertial forces during centrifugation.

31. A storage reservoir for blood as claimed at any one of the preceding claims wherein the flow control means includes a filter means which will control the flow of blood components from the first chamber through the flow control means on opening of the flow control means.

32. A storage reservoir for blood as claimed at claim 31 wherein the filter means comprises a porous element formed with a plurality of small openings.

33. A storage reservoir for blood as claimed at claim 31 wherein the filter means comprises a porous element formed from a matted fibrous material.

34. A method of separation of blood components from blood substantially as herein described utilising a storage reservoir for blood as claimed at any one of claims 7 to 34.