JPS62269037A - Portionwise serum sampler - Google Patents

Abstract

PURPOSE:To properly separate serum, by a method wherein the suction port of an apparatus is allowed to fall in a blood sampling tube subjected to centrifugal separation and, when serum is detected, the under surface position of serum is estimated from the detection position of serum to stop the suction port slightly above the estimated position. CONSTITUTION:The nozzle chip 16 at the leading end of the nozzle pie 14 supported by an arm 12 is allowed to fall from a start point (e) by a nozzle lowering motor 10. When the chip 16 falls to the upper surface 76 of serum, serum begins to be sucked and, when said serum is detected by the first electrode 26 and second electrode 30 in a tube 20, the position of the chip 16 is calculated from the number of rotations of the motor 10 and the under surface position 78 of the serum is estimated based on the quantity of the serum at each part. The falling of the chip is stopped slightly above the under surface position 78 and the serum 74 is properly separated from a separation agent 72 and blood clot 70.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Background of the Invention A. Technical Field The present invention relates to a serum fractionating device, and more specifically, to a device for fractionating serum separated in a blood collection tube.

B. Prior art and its problems There is a serum fractionation device that centrifuges blood collected in a blood collection tube and collects the serum separated above the centrifugation using a suction pump. In order to collect as much serum as possible, it is better to place the tip of the suction nozzle as close as possible to the interface with the blood clot below the serum. Therefore, lower the suction nozzle from above the blood collection tube. There is a soft landing method that makes a soft landing on the surface of the blood clot. However, there are some other components such as blood cells present at this interface, and if they are accidentally aspirated, they have a tendency to displace, reducing the accuracy of serum testing.

Therefore, in order to prevent the suction of other components at such an interface, for example, bead-like separating agents made of polystyrene or gel-like separating agents made of polyolefin have been used. In the case of a bead-shaped separation agent, the specific gravity is such that when it is mixed and centrifuged, it is distributed at the interface between serum and blood clot. Moreover, the gel-like separation agent is adhered to the bottom of the blood collection tube in advance due to its strong viscosity.

When centrifuged, the specific gravity is such that it is distributed at the interface.

In order to collect as much serum as possible after blood collection and separation, a soft landing method is preferred in which the tip of the suction nozzle is placed as close to the interface in the serum as possible, but this method has the disadvantage that gel on the nozzle tends to adhere. Gel separation agents are difficult to clean due to their strong viscosity, and when used together with beads, the beads may get mixed into the gel, causing various problems.

In order to avoid such problems, it is important to accurately control the vertical position of the nozzle when it is lowered from above within the blood collection tube to aspirate serum. For this purpose,
There is a method that uses a photodetector to detect the position of the blood clot surface or the separation agent surface at the interface. If the separation agent is milky white, optical detection will work properly, but if it is translucent, it will not work properly. Sometimes the plane doesn't work. Furthermore, if the separating agent adheres to the photodetecting element, it may malfunction and may not be detected properly.

OBJECTS OF THE INVENTION It is an object of the present invention to overcome the drawbacks of the prior art and to provide a serum fractionating device that can appropriately fractionate serum.

A serum collection device according to the present invention includes a suction port member inserted into a blood collection tube, and a conduit member for guiding serum sucked from the suction port, and a suction means for sucking centrifuged serum in the blood collection tube; a lowering means for lowering the suction port member into the blood collection tube and generating a signal in response to the lowering of the suction port member; and a first lowering means disposed at a predetermined position along the conduit member for detecting serum in the conduit member. a detection means, a stop means for stopping the lowering of the suction port member, and a control means for controlling the lowering means and the stopping means in response to the first detection means and the lowering means, and the control means controls the lowering means. When the suction port member is lowered from a predetermined reference position under control and the first detection means detects serum, the descending distance of the suction port member from the reference position is determined based on a signal from the lowering means, and the determined lowering distance is determined by the signal from the lowering means. The position of the lower surface of the serum in the blood collection tube is estimated from the distance, and the stopping means is controlled to stop the suction port member at the estimated lower surface position.

According to one feature of the present invention, the serum sorting device includes a second detection means disposed downstream of the conduit member in the serum suction direction and detects serum in the conduit member, and the control means includes a second detection means disposed downstream of the conduit member in the serum suction direction; The distance that the suction port member has descended from when the first detecting means detects serum to when the second detecting means detects serum is determined based on the signal from the descending means, and thereby the estimated lower surface position of the serum is determined. Correct l.

According to Seikan 1JI, a serum separation method in which separated serum in a blood collection tube is separated through a suction port member inserted into the blood collection tube involves suction while applying negative pressure to a conduit member connected to the suction port member. lowering the mouth member into the blood collection tube from a predetermined reference position, detecting serum in the conduit member at a first predetermined position along the conduit member, and starting from a reference position t when serum is detected; a step of calculating the descending distance of the suction port member, a step of estimating the position of the lower surface of the serum in the blood collection tube from the calculated descending distance, and a step of stopping the suction port member slightly above the estimated lower surface position. .

This estimating step includes detecting serum in the conduit member at a second predetermined position t downstream of the first predetermined position with respect to the serum suction direction of the conduit member; A step of calculating the distance that the suction port member has descended from detecting the serum at the second predetermined position to detecting the serum at the second predetermined position; It may also include the step of modifying the.

Embodiments of the serum fractionating device according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, in the embodiment of the serum fractionating apparatus according to the present invention, a nozzle vibrator 14 is supported by an arm 12 that moves vertically by rotation of a nozzle lowering motor 10. As shown in FIG. A suction port member, that is, a nozzle tip 16 is disposed at the lower end of the vibrator 14, and a motor lO rotates to rotate the arm 12.
When ? falls, to a predetermined position t below it? The nozzle tip 1B can be lowered into the blood collection tube 18 that is L21. A pinion 40 is connected to the output shaft of the motor 10, and the arm 12 is supported by a ridge 42 that engages with the pinion 40.

In this embodiment, a plurality of, for example ten, arms 12 are supported on the binion 42 . Therefore, in this embodiment, a plurality of blood collection tubes 18 are provided and blood can be collected from them at the same time. The nozzle pipe 14 is loosely secured to the arm 12, and a hook 44 is disposed in the middle of the vibrator 14. When the hook 44 is activated, the vibrator 14 is fixed, and even if the arm 12 is lowered, the vibrator 14 is not lowered.
Therefore, the configuration is such that the nozzle tip 16 does not descend below that level.

A flexible tube 20 is connected to the upper end of the nozzle pipe 14, and the other end of the latter is connected to a suction pump 24 through a pressure regulating valve 22. A first electrode 2B, a stopper 28, a second electrode 30, a stopper 32.7tIJ3 electrode 3B, and a stopper 38 are arranged in this order between the tubes 20 as shown in the figure.

Referring to FIG. 11i2, a configuration example of a control device that controls the lowering of the nozzle tip 1B of the present serum fractionating device is shown. This control device includes a host processor 50 including a processing system that controls the entire system, a nozzle position control unit 52 that is connected to the host processor 50 and includes a processing system that controls the nozzle tip 16, and a nozzle position control unit 5.
The nozzle lowering motor control section 54 is connected to the nozzle lowering motor 2 and controls the nozzle lowering motor lO. Nozzle position control section 52
A storage area that constitutes a first counter 56 and a second counter 58, which will be described later, is formed in the memory within the processing system. The nozzle lowering motor 10 has a tacho generator that generates clock pulses 60 (FIG. 1) in accordance with its rotation, and its clock output is connected to the nozzle lowering motor control section 54. The first counter 5B and the second counter 58 are each a counting area that counts this clock pulse 60.

The nozzle position control unit 52 controls the electrode 28°30 as shown in the figure.
and 36. It is connected to stoppers 2B and 38 and hook 44. A dip switch 62 is also connected to the control section 52. This is a manual switch for setting parameters Nmax, Ht, ΔY, and H, which will be described later, to desired values. Note that the electrode 36 and the stopper 38 are provided to prevent serum from being sucked into the suction pump 24.

As shown in FIG. 1, the blood collection tube 18 has an overall cylindrical shape with the same diameter. When blood is collected into a blood collection tube 18 containing a predetermined amount of a gel-like separation agent and subjected to centrifugation, a blood clot 70, a separation agent 72, and serum 74 are separated in the order shown in the figure. The amount va of serum 74 is Va=Vb(1-Ht), where Vb is the whole blood volume.
(1) However, Ht is a hematopoietic value, which is the ratio of blood clots to the total blood volume.As is well known, in humans, hematopoietic value 1 is approximately 45 to 6 oz. When the hematopoietic value is high and the amount of blood collected is small, the downward position t of the nozzle tip 1B must be strictly controlled in order to obtain the amount of serum necessary for the test.

Since the diameter of the blood collection tube 18 is almost the same throughout, the vehicle amount in equation (1) is equal to the bottom portion 211 of the blood collection tube 18.
It is proportional to the vertical distance from d. Therefore, if the vertical position a of the surface 76 of the serum 74 is known, the whole blood volume can be determined. On the other hand, since the amount of separating agent 72 is predetermined, b
The distance H between e is known. Therefore, from Equation 1 (1), the amount of serum 74, that is, the position ff1c of its interface with separation agent 72 (blood cell surface) can be predicted. The reference position, ie, the starting point e, to which the nozzle tip 16 returns is predetermined by the device, and the distance raG from there to the position d of the bottom of the blood collection tube 18 is also fixed.

Therefore, it is only necessary to measure the distance from the starting point e to the serum level a, that is, the whole blood Bvb is proportional to G-ea-H(2), and since G and H are known, the distance j
Just find @ea. In this embodiment, this is determined as follows.

The nozzle lowering motor control section 54 raises the nozzle tip IB to the starting point e, drives the suction pump 24 to generate suction negative pressure in the tube 20, and then drives the motor 10 to lower the tip 1B. lower. At this time, the nozzle position control section 52 starts counting by the first counter 5B. The tachogenerator of the motor 10 outputs clock pulses 60 according to its rotational speed. The first counter 56 thereby controls the nozzle lowering control section 54.
The signals corresponding to the clock 60 from .

When the nozzle tip 18 descends into the serum 74, serum begins to be sucked from the tip 1B, and the tip of the sucked serum in the tube 20 reaches the first electrode 26. This arrival is detected by the nozzle position control unit 52, and the ipsilateral gg unit 52 stops counting on the first counter 56 and starts counting on the second counter 58 at this time. Let the count value of the first counter 56 be Ml.

Similarly, the second counter 58 counts the signal corresponding to 0 from the nozzle lowering control section 54. When the tip of the aspirated serum in the tube 20 reaches the second electrode 8I30, it is counted by the nozzle position control section. 52, and the control unit 52 stops counting by the 7fS2 counter 58 at this time. Let the count value of the m2 counter 58 be N2.

Because the tube 20 is approximately uniform in diameter throughout its length, the amount of serum from the nozzle tip 16 to the location of the first electrode 26 is proportional to the distance along its length, and from the first electrode 26 to the second electrode 26. 1Fi, the amount of serum up to the position of pole 30 is proportional to the distance E along its length. Nozzle tip 1B
If F is the number of clocks 60 generated by the tacho generator of the motor 10 for a unit descending distance of /F
(3) The second term in parentheses () in the above equation is a term for correcting the influence on the count value of the first counter 5B due to variations in the pressure inside the tube 20, variations in the viscosity of the serum 74 to be aspirated, etc. It is. As will be seen from now on, this correction is performed based on the amount of serum aspirated from the first electrode 2G to the gII2 electrode 3Q.

Therefore, the distance x from the serum surface 76 to the separation agent surface 7 days is X-[(G-(Ml-82-0/E)/Fl-old(1-
Ht) (4) Therefore, the nozzle position control section 52
The integrated count value His of clock pulse 60 is expressed by the following formula (5)
When this is satisfied, the hook 44 corresponding to the blood collection tube 18 is driven to clamp the nozzle pipe 14, thereby stopping the nozzle tip 16 from descending. It stops very close to the lower surface 78.

His = ((Ml-N2eD/E)/F+X) φ
FThis is calculated from equation (4) as N15=[(Ml -82・D/E)/F+(G-H
-(Nl-N2-0/E)/F) (1-Ht)]・F
= F(GH)(1-Ht)+(Ml-82・D/
E) It (5) For safety, the nozzle tip 16
Considering the downward margin ΔY of
-D/E)Ht-F-ΔY In formula (8), weighing,
E, F, G, and ΔY are fixed depending on the device, and the amount H is also generally fixed if blood collection tubes 18 of the same standard are used, and the amount Ht can also be regarded as constant. The variables that differ accordingly are the counter count old and N2.

Note that if the cross-sectional area of the blood collection tube 18 is Sl, and the cross-sectional area of the nozzle pipe 14 and tube 20 is 52, then the serum amount Xx
SI is the serum amount (DIE) S between the origin e and the second electrode 30
If it is less than 2, the nozzle tip 16 will reach the separating agent 72, so this condition limits the lowest point of descent of the nozzle tip 1B. The maximum descending point is defined as the maximum permissible value Nmax of the integrated count value Nis of Equation 1 (6), which is input from the dip switch 82 and the nozzle position is controlled by the controller 5.
Set to 2.

In this way, the nozzle position control unit 52 independently performs the above-described nozzle lowering position control for each of the ten blood collection tubes 18 included in the preparative collection device of this embodiment, and moves the hooks 44 individually to control the nozzle position. Stop the lowering of the chip 1B. An example of this operational flow is shown in FIGS. 3A and 3B.

IV, release■! 1. Specific Effect According to the present invention, the lowering position of the serum suction nozzle is determined by measuring the whole blood volume and estimating the serum volume. Therefore, even if the detection device uses a type of separation agent that is difficult to detect on the surface of the turf agent, serum can be appropriately separated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing an embodiment of a serum fractionating device according to the present invention. FIG. 2 is a block diagram showing an example of the configuration of a control device for controlling the lowering of a nozzle tip with the device shown in FIG. 3A and 3B are flowcharts showing an example of the operation flow of the control device shown in FIG. ,,arm+8. , nozzle tip 18. ,, blood collection tube 28.30. , electrode 44 , hook 52 , nozzle position control section 54 , nozzle lowering motor control section 62 , dip switch

Claims (1)

[Scope of Claims] 1. A suction means that includes a suction port member inserted into the blood collection tube and a conduit member for guiding the serum sucked from the suction port, and sucks the separated serum in the blood collection tube; a lowering means for lowering the suction port member into the blood collection tube and generating a signal in response to the lowering of the suction port member; a first detection means for detecting; a stop means for stopping the lowering of the suction port member; and a control means for controlling the lowering means and the stopping means in response to the first detection means and the lowering means; The control means controls the lowering means to lower the suction port member from a predetermined reference position, and when the first detection means detects serum, the control means controls the lowering means to lower the suction port member from a predetermined reference position, and when the first detection means detects serum, the first detection means detects the serum. Calculating the descending distance of the suction port member from the reference position based on a signal from the descending means, estimating the position of the lower surface of the serum in the blood collection tube from the calculated descending distance, and controlling the stopping means. and stopping the suction port member slightly above the estimated lower surface position. 2. The conduit member has a second detection means for detecting serum in the conduit member downstream with respect to the serum suction direction, and the control means detects the serum after the first detection means detects the serum. The distance that the suction port member has descended until the detecting means detects the serum is calculated based on the signal from the lowering means, and the estimated lower surface position of the serum is thereby corrected. A serum fractionating device according to claim 1. 3. A serum collection method in which separated serum in a blood collection tube is collected through a suction port member inserted into the blood collection tube,
The method includes the steps of: lowering the suction port member from a predetermined reference position into the blood collection tube while applying negative pressure to a conduit member connected to the suction port member; detecting the serum in the conduit member at the position; calculating the descending distance of the suction port member from the reference position when the serum is detected; A method for separating serum, comprising: estimating the position of the lower surface of the serum; and stopping the suction port member slightly above the estimated position of the lower surface. 4. The estimating step includes: detecting serum in the conduit member at a second predetermined position downstream of the first predetermined position with respect to the serum suction direction of the conduit member; a step of calculating the distance that the suction port member has descended from detecting the serum at the second predetermined position to detecting the serum at the second predetermined position; 4. The serum collection method according to claim 3, further comprising the step of correcting the lower surface position of the serum.