JP3461618B2 - Blood coagulation time measuring method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood coagulation time measuring method and apparatus, and more particularly to a blood coagulation time measuring method and apparatus using a pressure detector.

[0002]

2. Description of the Related Art Various methods have been proposed for measuring the coagulation time of blood, and the methods that have been particularly put to practical use are roughly classified into a scattered light method and a magnetic sensor method. In the scattered light method, as shown in FIG. 1, a test tube (cuvette) 1 for containing blood is irradiated with light from a light source 2 such as a laser light source through a condenser lens 3, and the scattered light is measured by a backscattered light sensor 4 or It is detected by the forward scattered light sensor 5. 6
Is an absorption tube that prevents reflection of transmitted light. In measuring the coagulation time, first, a certain amount of blood is placed in the test tube 1, a certain amount of reagent is sucked by a pipette (not shown), and this is mixed with the blood in the test tube 1 and scattered from the time of mixing. The scattered light sensor 4 or 5 starts measuring the light. As blood coagulation progresses, the scattered light rapidly increases at a certain point and finally saturates. Therefore, the coagulation time is set according to an appropriate standard such as the point with the largest gradient (the differential value is maximum). . On the other hand, in the magnetic sensor method, as shown in FIG. 2, a steel ball 9 is inserted into a test tube 7 having a constant diameter, and the magnet 8 is placed outside to float the steel ball 9 at a fixed position. And the light receiving unit 13 are arranged to face each other. Separately from this, the light source 10 and the light receiving unit 11 are arranged above the test tube 7 to form a reagent sensor. When measuring the coagulation time, first, a certain amount of blood is stored in the test tube 7, and a certain amount of reagent is sucked by a pipette (not shown) and added to the test tube 7. The detection of light by the light receiving unit 11 automatically starts mixing of blood and reagent and counting of time, and the test tube 7 is repeatedly moved up and down by an elevating device (not shown). The blood and the reagent are mixed by the steel balls 9, and the viscosity of the blood increases as the reaction coagulation progresses, and the viscosity rapidly increases at a certain point, so that the steel balls 9 can no longer stand still and vibrate up and down. The count 9 is stopped when the light source 9 and the light receiving unit 13 deviate from the light path 9. The time until this stop or the time corrected accordingly is defined as the coagulation time.

[0003]

However, in the scattered light photometric method, the amount of scattered light depends on the color and turbidity of the sample, so that the measured values are likely to vary from sample to sample, and whole blood cannot be used. It is necessary to use plasma that has been subjected to pretreatment such as centrifugation to remove turbidity from blood, and the measured values are easily affected by extraneous light. There are problems such as. On the other hand, in the magnetic sensor method, the precision of the inner diameter and the wall thickness of the transparent glass container 7 directly affects the measured value, so there is a problem that a precise glass container is required, and there is a problem that a small amount of sample and specimen cannot detect. Yes, it is necessary to purify blood in the same way as the accuracy becomes unstable depending on the sample. Furthermore, when incinerating and discarding the steel ball and the test tube after use, it is necessary to separate them from each other. . Therefore, an object of the present invention is to provide a simple measuring method and device that can use whole blood as it is. Another object of the present invention is to provide a measurement method and device which are highly accurate but inexpensive.

[0004]

According to the present invention, a blood coagulation reagent is added to blood to form a mixed solution, and a pump is used to repeat the mixed solution on a tip whose tip is immersed in the mixed solution. pressure portion while pumped continuously measuring the pressure in the pump, pressure value measured starts to rise sharply
Measured from the time of adding the blood coagulation reagent using force measurement values
There is provided a blood coagulation time measuring method characterized in that the determined coagulation time is determined. The present invention also provides a sample reaction tank for containing blood and a blood coagulation reagent, a tip that can be inserted into and removed from the reaction tank, a piston-cylinder type pump connected to the tip, and a reciprocating motion of the piston. There is provided a blood coagulation time measuring device including a power means for controlling the pressure, a pressure detector for measuring the pressure in the pump, and a means for determining a blood coagulation time from a portion where the pressure measurement value starts to rise rapidly . In particular, it is possible to employ a simple and inexpensive mechanism for connecting the piston to a motor as a power means through a reciprocating motion generating means including a ball screw and a ball screw interlocking plate.

[0005]

In the present invention, the coagulation state can be detected by monitoring the pressure value of the pressure detector installed in the pump while repeatedly injecting the mixed liquid of blood and coagulation reagent into the chip by the pump. When pressure fluctuations are monitored using the pressure values read during inhalation and discharge, and peak values of the pressure values are extracted and plotted, a temporal change as shown in FIG. 5 is obtained, so the time point at which the pressure changes rapidly is read from the graph. Alternatively, the blood coagulation time can be easily determined by automatically calculating the pressure value data stored in the microcomputer.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to FIG. In FIG. 3, reference numeral 11 denotes a thermostatic chamber with a rubber heater, which is controlled by a computer so as to maintain a standard temperature of 37 ± 0.5 ° C. on the basis of the value of the temperature detector H installed therein. . This constant-temperature bath 11 is provided with a chip heat-retaining bath C, in which unused clean chips 13 are inserted. Further, the constant temperature bath 11 is provided with a reagent bath T such as a test tube containing a blood coagulation measurement reagent, and a sample reaction bath 12 for containing a sample blood and carrying out a blood coagulation reaction. ,
All of T and 12 are maintained at almost the same temperature. A horizontal movement / elevation device (not shown), to which the motor M is fixed, is arranged above the constant temperature bath 11, and the motor M described below is provided.
It can move and move up and down among the heat-retaining tank C, the reagent tank T, and the reaction tank 12 by supporting an intake / exhaust mechanism including. A chip 13 is vertically inserted into the sample reaction tank 12. The lower end portion of the tip 13 penetrates into the blood in the sample reaction tank 12. A pump including a cylinder 18 and a piston 14 is installed on the upper end of the tip 13, and the cylinder 18 is fixed to a part of the lifting device. Cylinder 18
Is equipped with a pressure detector S for detecting the pressure inside. A ball screw 15 and a ball screw interlocking plate 16 are connected to the piston 14 of the pump. Ball screw 15
Is connected to a motor M via a coupling 17. That is, when the motor M rotates the ball screw 15, the ball screw interlocking plate 16 moves up and down in conjunction with each other. Since the piston of the piston 14 connected to the interlocking plate 16 is repeatedly moved up and down by the vertical movement of the interlocking plate 16, the air in the cylinder 18 is discharged and sucked. At the same time as the blood and the blood coagulation measuring reagent are stirred, the mixed solution is repeatedly sucked and discharged into the chip 13. The pressure detector S installed in the cylinder 18 can detect the coagulation state. When the pressure fluctuation is monitored by the action of the intake / exhaust mechanism, the coagulation progresses and the viscosity increases, and the pressure value correspondingly increases, so it is said that when the pressure value suddenly increases, it solidifies. I can judge. Alternatively, the ball screw interlocking plate 16
A plurality of pistons 14, a cylinder 18, and a sensor S
If a plurality of chips 13, a reagent tank T, and a sample reaction tank 12 are provided correspondingly, a plurality of samples may be tested at the same time.

The operation of the method and apparatus of the present invention will now be described. By operating a horizontal movement / elevation device (not shown), first, the suction / discharge mechanism is moved to the tip heat-retaining tank C, and the heat-retained tip 13 is fixed to the lower end of the cylinder 18. Note that this step may be automatic or manual. In the case of automatic operation, the chip heat-retaining tanks C are arranged in a coordinate manner, the chips are inserted one by one, and the chips are sequentially taken out by an automatic allocation means or the like. Next, the suction / discharge device moves the chip 13 to the reagent tank T, sucks the blood coagulation measurement reagent into the chip 13 in the reagent tank T, and the suction / discharge device further moves the chip 13 into the sample reaction tank 12 as shown in the figure. Move and dispense reagent into it. Next, when the motor M is driven, the shaft 17 rotates and the ball screw 15 and the ball screw interlocking plate 16 are rotated.
Is converted into an up-and-down reciprocating motion, and the mixture of blood and reagent is repeatedly sucked and discharged into the chip 13 through the piston 14 and the cylinder 18.

The coagulation state can be detected by monitoring the value of the pressure detector S installed in the cylinder 18 while continuing the above operation. When the pressure fluctuation is monitored by using the pressure value read at the time of suction by the action of the suction / discharge mechanism, the pressure value becomes a wave as shown in FIG. It suffices to take the actual peak values shown and plot them as shown in FIG. 5, and the blood coagulation time can be easily determined by applying these to a simple calculation by the microcomputer. At the initial stage, there is no change in the pressure value because the viscosity is low, but as coagulation progresses, the viscosity increases and the pressure value also increases, so the pressure value compared to the pressure value at the start It can be judged that the solidification has occurred when the temperature has risen sharply. For example, in general, the determination of the coagulation time, which has been conventionally performed by manual work and visual observation, is relatively accurate in the case of a skilled person, and is standardized, so that it is increased by 20% from a preferable baseline in comparison therewith. It is good to judge it as the freezing point when you do.

According to the method and apparatus for measuring the coagulation time by the pressure detector of the present invention, whole blood can be used as it is, and the time required for the determination can be shortened. The color, turbidity and extraneous light of the sample are irrelevant, so only the coagulation time can be detected accurately and with good reproducibility, and observation with the naked eye is possible. According to the actual measurement, the variation is less than half that of the conventional mechanical method. Furthermore,
Small amounts of blood and reagents are sufficient. Since the ratio between the blood amount and the reagent amount is constant, it is advantageous that the blood sampling amount and the reagent amount can be small enough to detect a trace amount. Further, since the chip material may be made of plastic, it is easy to dispose at the end of the inspection unlike the conventional magnetic detector method. Next, an example in which the present invention is actually applied to measurement of blood coagulation time will be shown.

Measurement Example Blood coagulation time was measured using the apparatus shown in FIG. As the sample, blood collected from the subject was used as it was, and 24 μl of a commercially available standard solution for calibration and 200 μl of a commercially available blood coagulation reagent were used. Time measurement was started from the moment when the reagent was injected into the sample blood, and suction and discharge were repeated. Fig. 5 shows a plot of the pressure peak (relative value).
Is. The coagulation time was defined as the point where the pressure increased by 20% or more from the baseline. When repeatedly tested, the variation was about 1.3%.

In the conventional scattered light method, the reagent is usually 25
About 0 μl, the reagent is usually 200 in the conventional magnetic detector method.
Since it is about μl, it can be seen that the method of the present invention requires a small amount.

[0012]

According to the present invention, since the blood coagulation time is detected by the pressure detector, the measured value may be the color or turbidity of the sample, external light,
Since the test can be performed on whole blood without depending on the dimensional accuracy of the test tube and there is no defect that the measured value becomes unstable depending on the sample, the whole test time is greatly shortened. According to the present invention, a very small amount of blood can be accurately detected.

[Brief description of drawings]

FIG. 1 is a conceptual view showing a conventional blood coagulation time measuring device by a light scattering method.

FIG. 2 is a conceptual diagram showing a blood coagulation time measuring device by a conventional magnetic detector method.

FIG. 3 shows a blood coagulation time measuring device by the pressure detector method of the present invention.

FIG. 4 is a graph showing a relationship between a pressure value of a pressure sensor and time when the device of the present invention is used.

FIG. 5 is a graph showing a relationship between a pressure value peak value of a pressure sensor and time when the device of the present invention is used.

[Explanation of symbols]

11: Constant temperature bath 12: Sample reaction tank (blood tank) 13: Chip 14: Piston 15: Ball screw 16: Ball screw interlocking plate 17: Coupling 18: Cylinder C: Chip heat insulation tank T: Reagent tank M: Motor S: Pressure detector H: Temperature detector

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-58-137761 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 33/86

Claims (4)

(57) [Claims] 1. A blood coagulation reagent is added to blood to form a mixed solution, and a pump is used to repeatedly inhale and discharge the mixed solution to a chip whose tip is immersed in the mixed solution. The pressure is continuously measured, and the blood pressure is measured using the pressure measurement value at the portion where the measured pressure value starts to rise rapidly.
A method for measuring blood coagulation time, which comprises determining a coagulation time measured from the time of addition of a coagulation reagent . 2. A sample reaction tank containing a mixture of blood and a blood coagulation reagent, a chip insertable into and removable from the reaction tank, a piston-cylinder type pump connected to the chip, and the piston. A blood coagulation time measuring device comprising a power means for reciprocating the pump, a pressure detector for measuring the pressure in the pump, and means for determining the blood coagulation time from the portion where the pressure measurement value starts to rise rapidly . 3. The blood coagulation time measuring device according to claim 2, wherein the piston is coupled to a motor which is a power means through a reciprocating motion generating means including a ball screw and a ball screw interlocking plate. 4. The blood coagulation reagent is contained in a reagent tank,
The blood coagulation time measuring device according to claim 2, wherein the reagent tank, the sample reaction tank, and the chip are housed in a constant temperature tank.