JP5029638B2 - Blood coagulation analyzer - Google Patents

Description

  The present invention relates to a blood coagulation analyzer for measuring blood coagulation time.

  In blood coagulation analysis, a predetermined reagent is added to a blood sample (plasma), and the time from when the reagent is added until a clot is formed is measured. Conventionally, such blood coagulation analysis has been performed manually by the examiner, but in recent years, from the addition of reagents to specimens, the detection of clot formation and the calculation of coagulation time are automatically performed. Blood coagulation analyzers that can be used have been developed and are widely used in fields such as clinical tests.

  In the blood coagulation analyzer as described above, a coagulated mass is usually obtained by irradiating a reaction liquid (blood sample added with a predetermined reagent) with a certain amount of light and continuously measuring the amount of light scattered from the reaction liquid. Is detected (see, for example, Patent Document 1). FIG. 4 shows an ideal reaction profile in the blood coagulation reaction, in which the horizontal axis represents the elapsed time from the time of reagent addition, and the vertical axis represents the amount of scattered light from the reaction solution. As shown in the figure, in a normal blood coagulation reaction, when a certain amount of time has passed since the addition of the reagent, a clot is formed and the amount of scattered light rises rapidly, and then the clot is formed by completing the formation of the clot. The light intensity is saturated. Therefore, it is possible to detect the formation of the coagulated mass by analyzing such a change in the amount of scattered light over time, and the coagulation time can be calculated based on this.

  The procedure for calculating the coagulation time in the conventional blood coagulation analyzer will be described below with reference to FIG. First, the blood coagulation analyzer starts measurement of the amount of scattered light by irradiating a cell containing a blood sample with light, and then adds a predetermined reagent to the sample. Then, the scattered light quantity data sequentially obtained at predetermined time intervals is analyzed in real time, and the coagulation end point a is detected based on the change with time of the scattered light quantity. Here, for example, an inflection point or a saturation arrival point of the reaction profile is detected using time differentiation or second order differentiation of the scattered light amount, and this is set as a coagulation end point a.

  Next, it is determined whether or not the amount of scattered light at the coagulation end point a detected above is equal to or greater than a predetermined threshold (hereinafter referred to as “light amount threshold”). End measurement. Thus, by terminating the measurement when a point satisfying the condition is found, the analysis time can be shortened and the throughput in multi-sample measurement can be improved.

  Subsequently, a time at which 1 / N (N is a predetermined number greater than 1) of the amount of scattered light at the coagulation end point a is obtained, and this is set as the coagulation point b, and the process from the addition of the reagent to the coagulation point b is performed. The coagulation time is calculated by obtaining the time. The above N is a value that varies depending on the reagent and apparatus used for the measurement, and is determined in advance in consideration of the consistency with the measurement result obtained by a technique used by a skilled inspector.

  On the other hand, if the amount of scattered light at the coagulation end point a is less than the light amount threshold, the coagulation end point a is canceled and the measurement is continued. After that, if a point that satisfies the condition is not found before the predetermined time elapses, it is determined that measurement is impossible and the user is notified accordingly.

Japanese Patent Laid-Open No. 4-318463

  However, the reaction profile in FIG. 4 is ideal only, and the amount of scattered light may not show the ideal change as described above depending on the difference in the inspection item (that is, the difference in the added reagent or the like). For example, in the measurement of the APTT (Activated Partial Thromboplastin Time) item, as shown by the solid line in FIG. 5, the portion where the change in the amount of scattered light temporarily decreases in the initial reaction (this is referred to as “pre-peak”). May occur). In addition, in a specimen having a long coagulation time due to heparin administration or factor deficiency, a slight change in the amount of scattered light may be seen before the peak due to the original coagulation reaction appears.

  In order to prevent the determination of the coagulation time based on such a pre-peak or subtle light quantity change, it is conceivable to set the light quantity threshold value high. For example, in the case of a specimen showing a reaction profile as shown by the solid line in FIG. 5, if the light intensity threshold is set to 500, the original peak that appears after ignoring the pre-peak can be used for the calculation of the coagulation time.

  However, when the light amount threshold is set high, even in the case where the amount of change in the amount of scattered light is small, such as a low fibrinogen sample (Fib 100 mg / dl or less), even when the coagulation end point is determined based on the original peak, In some cases, the amount of scattered light at the coagulation end point a does not satisfy the light amount threshold, and the coagulation time cannot be calculated. For example, in the case of a specimen showing a reaction profile such as a one-dot chain line in FIG. 5, if the light amount threshold is 250, the amount of scattered light at the coagulation end point exceeds the threshold, so that the coagulation time can be measured. If set, measurement is impossible. In such a case, it is necessary to increase the amount of the sample and perform a reexamination, or to perform a measurement using a method.

  Therefore, in addition to the above-described calculation function of the coagulation time, an apparatus having a noise determination function for determining whether or not the calculated coagulation time is based on a normal coagulation reaction has been developed. For example, in the APTT item, there is a dispersion relationship as shown in FIG. 6 between the amount of scattered light and the coagulation time at the freezing point, and data in the area below the noise judgment line in the figure does not occur in a normal coagulation reaction. Is found by actual measurement. Therefore, if the result of the blood coagulation analysis as described above is below the noise judgment line in FIG. 6, it is judged that there is a risk of noise, and the measurement report describing the measurement result is output when the measurement report is output. The result of noise judgment was added to alert the user. By doing in this way, even if it is a case where a light quantity threshold value is set low, it can prevent that the incorrect coagulation time by a pre peak etc. is employ | adopted as a test result.

  However, in the blood coagulation analyzer having the conventional noise determination function, the measurement of the scattered light amount is terminated when the coagulation end point satisfying the light amount threshold is detected, and then the noise determination as described above is performed. When the wrong solidification end point was determined based on the pre-peak or the like, the normal peak that should appear later was not observed. For this reason, when the user refers to the measurement report as described above and determines that the reliability of the determination result of the coagulation time is low, it is necessary to change the conditions and perform the measurement again, which is troublesome.

  The present invention has been made in view of the above points, and the object of the present invention is to obtain a blood coagulation that can appropriately calculate the coagulation time by a single measurement even for a pre-peaked specimen or a low fibrinogen specimen. An analyzer is provided.

A blood coagulation analyzer according to the present invention, which has been made to solve the above problems,
a) a measuring means for irradiating a blood sample with light to measure the amount of scattered light from the blood sample;
b) Coagulation that obtains a scattered light amount value measured by the measuring means at a predetermined time interval and detects a coagulation end point based on a change over time in the scattered light amount value after a predetermined reagent is added to the blood sample. End point detection means;
c) The point at which the amount of scattered light reaches 1 / N (N is a predetermined value of 1 or more) of the amount of scattered light at the end point of coagulation is defined as the freezing point, and the elapsed time from the point of addition of the reagent to the coagulation point is defined as the coagulation time. A coagulation time calculating means for calculating;
d) determining means for determining whether the coagulation time is normal;
e) When the determination means determines that the coagulation time is normal, the measurement by the measurement means is terminated; otherwise, the measurement by the measurement means is continued and after the start of the continuous measurement Assuming that each time point is the end point of coagulation, the calculation of the coagulation time by the coagulation time calculation unit and the determination by the determination unit are sequentially executed, and if the determination unit determines that the coagulation time is normal, Control means for terminating the measurement by the measuring means;
It is characterized by having.

  In the blood coagulation analyzer according to the present invention, the control means restarts the detection of the coagulation end point by the coagulation end point detection means when the rising of the amount of scattered light is confirmed during the continuous measurement. Thus, if the end point of coagulation is detected after the start of the rise, it is desirable to execute the calculation of the coagulation time by the coagulation time calculation unit and the determination by the determination unit.

  In addition, the said determination means shall determine whether this coagulation time is normal from the combination of the amount of scattered light in the said solidification point, and the said coagulation time, for example.

  According to the above configuration, when the coagulation end point is determined and the coagulation time is calculated based on the light amount change not derived from the original coagulation reaction such as a pre-peak, the coagulation time is normal by the determination unit. Measurement of the amount of scattered light is continued until it is determined that the normal coagulation time is determined. Therefore, even for a specimen that generates the above-described pre-peak or the like, the clotting time can be calculated based on the subsequent normal peak, and a highly reliable blood clotting analysis can be performed.

1 is a block diagram showing a schematic configuration of a blood coagulation analyzer according to an embodiment of the present invention. The flowchart explaining the calculation procedure of the coagulation time in the blood coagulation analyzer of the same Example. The figure for demonstrating the calculation method of the coagulation time in the blood coagulation analyzer of the Example. The figure which shows the ideal reaction profile in a blood coagulation analysis. The figure which shows the other example of the reaction profile in a blood coagulation analysis. The figure explaining the determination method of whether the calculated coagulation time is normal.

  Hereinafter, a blood coagulation analyzer according to an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of the blood coagulation analyzer of this embodiment.

  The measurement unit 10 includes a cell holding unit 12 for holding a scattered light measurement cell (cuvette) 11, a light source 13 for irradiating the cell 11 accommodated in the cell holding unit 12, and a light source 13. The light detector 14 for detecting the scattered light which arises from the said cell inside by light irradiation of is provided. The cell holding part 12 is provided with a heating means (not shown) so that the liquid in the cell 11 can be maintained at a constant temperature.

  The cell transfer mechanism 15 takes out an empty cell 11 from a cell supply unit (not shown) in which a plurality of unused cells are stored, sets the cell 11 in the cell holding unit 12, and sets the used cell 11 to the cell holding unit 12. And a manipulator or the like for grasping and moving the cell 11 is provided.

  The sample dispensing mechanism 16 is for injecting a predetermined amount of blood sample (plasma or a diluted product thereof) into the cell 11 accommodated in the cell holding unit 12, for example, accommodating a plurality of sample containers containing blood samples. A possible sample tray, a pipette that sucks and discharges the specimen, and a drive mechanism for moving the pipette between the sample tray and the cell holding unit can be used.

  The reagent dispensing mechanism 17 is for injecting a predetermined reagent (coagulation reagent) into the cell 11 held in the cell holding unit 12. For example, the reagent dispensing mechanism 17 sucks the reagent and holds a reagent container containing the reagent. A pipette to be discharged and a drive mechanism for moving the pipette between the reagent container and the cell holding unit can be used. Furthermore, the reagent dispensing mechanism 17 has a function of sending an addition notification signal to that effect to the control unit 19 described later when a reagent is added to the cell 11 in the cell holding unit 12.

  The data processing unit 18 samples the detection signals sequentially output from the photodetector 14 of the measurement unit 10 at predetermined time intervals (for example, 0.1 second intervals) and converts them into digital data (light amount data). The coagulation time is calculated by analyzing in real time according to a predetermined algorithm. The operation of each of the above-described units is comprehensively controlled by the control unit 19, and a user instruction is input to the control unit 19 via an operation unit 20 including a keyboard and various operation buttons. The analysis result by the data processing unit 18 is displayed on a monitor 21 connected to the control unit 19 or printed out by a printer (not shown). The data processing unit 18 and the control unit 19 can be configured by, for example, a microcomputer equipped with a predetermined program, and according to the program, the measurement unit 10, the cell transfer mechanism 15, and the sample dispensing mechanism 16 are configured. The operation of the reagent dispensing mechanism 17 is controlled, and various calculations in the data processing unit 18 are executed.

  Hereinafter, the measurement procedure of the coagulation time using the blood coagulation analyzer of the present embodiment will be described with reference to the flowchart of FIG. Here, description will be made by taking as an example measurement of a specimen that generates a reaction profile as indicated by a solid line or a one-dot chain line in FIG.

  When starting the measurement, first, an empty cell 11 is set in the cell holding unit 12 by the cell transfer mechanism 15, and a predetermined amount of sample is injected into the cell 11 by the sample dispensing mechanism 16. Next, measurement of the amount of scattered light from the specimen in the cell is started by the measurement unit 10 (step S31), and a detection signal from the photodetector 14 is output to the data processing unit 18. The detection signal is converted into digital data (light quantity data) by the data processing unit 18.

  Thereafter, a predetermined amount of reagent is added to the cell 11 by the reagent dispensing mechanism 17 (step S32), and simultaneously, an addition notification signal is output from the reagent dispensing mechanism 17 to the control unit 19. Upon receiving this addition notification signal, the control unit 19 causes the data processing unit 18 to start searching for a coagulation end point based on the light amount data (step S33). At this time, the data processing unit 18 detects a predetermined stage from when the amount of scattered light rises to a constant value after addition of the reagent, for example, an inflection point of the reaction profile, a saturation arrival point, or the like as a coagulation end point. . As a method for detecting such a coagulation end point, a conventionally known method can be used. For example, the coagulation end point can be detected using a value obtained by differentiating the scattered light quantity with time or second-order differentiation. For example, at this time, in the example of FIG. 3, the time point of 68 seconds is detected as the coagulation end point a1 in both the specimens corresponding to the solid line and the one-dot chain line.

  In addition, when the coagulation end point is not detected until the predetermined maximum measurement time (for example, 200 seconds from the addition of the reagent) has elapsed (that is, No in step S33 and Yes in step S34), measurement is impossible. Determination is made and the light quantity measurement ends (steps S35 and S39), and a message to that effect is displayed on the monitor 21 (step S40).

  When the coagulation end point is detected as described above (Yes in step S33), it is subsequently determined whether or not the amount of scattered light at the coagulation end point is greater than or equal to a predetermined light amount threshold value (step S36). . Here, if the scattered light amount is less than the light amount threshold value (No in step S36), the process returns to step S33 to resume the search for the coagulation end point, and steps S33 and S34 until a point satisfying the light amount threshold value is found. , And S36 are repeatedly executed.

  On the other hand, when the amount of scattered light at the coagulation end point is equal to or greater than the light amount threshold (Yes in step S36), the amount of light is 1 / N (N is a predetermined value greater than 1) of the amount of scattered light at the coagulation end point. The arrival time is determined and this is set as the freezing point. In the example of FIG. 3, the light amount threshold value is set to 250, and the scattered light amount at the coagulation end point a1 (68 seconds) of the specimen corresponding to the solid line and the alternate long and short dash line exceeds the light amount threshold value. The time (30 seconds) when the light amount reaches 1 / N of the light amount is the solidification point b1.

  Next, the elapsed time from the reagent addition time to the freezing point is defined as a freezing time, and it is determined whether or not the combination of the freezing time and the amount of scattered light at the freezing point is a combination that can appear in a normal freezing reaction (step) S37). As described above, the solidification time and the amount of scattered light at the solidification point in a normal solidification reaction are clearly shown by measurement as shown by the circles in FIG. Therefore, if the noise determination line is determined as shown in the figure and the result of plotting the amount of scatter of the freezing point and the coagulation time obtained above is located in the upper right region (normal region) of the noise determination line, It can be determined that the coagulation time is normal.

  When it is determined that the coagulation time is normal (Yes in step S37), the coagulation time is determined as the final measurement result (step S38), and the measurement of the amount of scattered light by the measurement unit 10 is completed. (Step S39) The measurement result is displayed on the monitor 21 (Step S40).

  On the other hand, if it is determined that the coagulation time is not normal (No in step S37), the coagulation time is canceled and the measurement of the scattered light amount is continued. In the example of FIG. 3, the coagulation time is 30 seconds. When the amount of scattered light at the freezing point b1 and the coagulation time are plotted in the graph of FIG. The light intensity measurement is continued.

  When the measurement of the amount of scattered light is continued as described above, the clotting time is calculated and determined in the same manner as described above, assuming that each subsequent time point is the clotting end point, and the clotting time is normal. The light quantity measurement is continued until it is determined that That is, when the data processing unit 18 acquires the light amount data after the start of the continuous measurement, the time when the light amount reaches 1 / N of the scattered light amount is obtained and used as a temporary freezing point, and the temporary freezing point is reached from the reagent addition. The elapsed time until is calculated as a temporary coagulation time. Next, it is determined using the noise determination line in FIG. 6 whether the combination of the amount of scattered light at the temporary solidification point and the temporary solidification time is normal. Such calculation and determination of the temporary coagulation time are repeatedly executed every time the data processing unit 18 acquires new light quantity data (or at predetermined time intervals), and the temporary coagulation time is normal. Is determined (Yes in step S42), the temporary coagulation time at that time is determined as the coagulation time of the sample (step S43), and the light quantity measurement is terminated (step S46). For example, in the case of the sample of the one-dot chain line in FIG. 3, when the measurement is continued up to 160 seconds, the combination of the amount of scattered light at the provisional coagulation point b2 and the provisional coagulation time obtained as the provisional coagulation end point a2. 6 exceeds the noise judgment line in FIG. 6, and the coagulation time (62 seconds) at this time is determined as the coagulation time of this specimen.

  Further, during the execution of the continuous measurement as described above, before it is determined that the coagulation time is normal (that is, before Step S42 becomes Yes), the amount of scattered light as shown by the solid line in FIG. When the rising (rapid increase) is confirmed (Yes in step S41), the data processing unit 18 returns to step S33, and after the rapid increase start time (for example, when the change rate of the scattered light amount exceeds a predetermined value). The search for the coagulation end point is started again based on the light quantity data, and the detection and determination of the coagulation end point (step S36), the calculation and determination of the coagulation time (step S37), and the like are performed in the same manner as described above. At this time, in the specimen indicated by the solid line in FIG. 3, the time point of 152 seconds is detected as the coagulation end point a3 in step S33, and in step S36, the amount of scattered light at the coagulation end point a3 is determined to be greater than or equal to the light amount threshold value. Further, the solidification time (128 seconds) is obtained by setting the time at which the light amount reaches 1 / N of the scattered light amount at the solidification end point a3 as the solidification point b3, and it is determined in step S37 that the solidification time is normal. In this example, 1 / N of the amount of scattered light at the coagulation end point a3 is obtained from a baseline where the amount of scattered light at the start of measurement is 0. Good. Then, the coagulation time is determined as the final measurement result (step S38), the light quantity measurement is completed (step S39), and the measurement result is displayed on the monitor 21 (step S40).

  Note that, when continuous measurement is performed until a predetermined time has elapsed, if both Step S41 and Step S42 are No (that is, Yes in Step S44), it is determined that the sample cannot be measured. Then, the light quantity measurement is finished (steps S45 and S46), and a message to that effect is displayed on the monitor 21 (step S47). The “predetermined time” may be a time from the time of reagent addition or a time from the start of continuous measurement.

  Thus, according to the blood coagulation analyzer according to the present embodiment, the original coagulation reaction such as a pre-peak can be achieved even when the threshold value of the scattered light amount (light amount threshold value) at the coagulation end point as described above is set low. Since it is possible to prevent the coagulation time from being determined based on the change in the amount of light that does not depend on, and the measurement is continued until a normal coagulation time is obtained, such as the APTT item and LA (Lupus Anticoagulant) item It is possible to obtain highly reliable measurement results without performing complicated re-measurement for various measurement items such as pre-peaks and various samples such as low fibrinogen samples.

  In the above embodiment, in step S37 and step S42, it is determined whether or not the coagulation time is normal from the combination of the amount of scattered light at the coagulation point and the coagulation time. Based on whether the integrated value of the amount of scattered light from the addition point to the freezing point is a predetermined threshold or more, or whether the combination of the integrated value and the solidifying point is a combination that can appear in a normal coagulation reaction It is also possible to determine whether the coagulation time is normal.

DESCRIPTION OF SYMBOLS 10 ... Measurement part 11 ... Cell 12 ... Cell holding part 13 ... Light source 14 ... Photo detector 15 ... Cell transfer mechanism 16 ... Sample dispensing mechanism 17 ... Reagent dispensing mechanism 18 ... Data processing part 19 ... Control part 20 ... Operation part 21 ... Monitor

Claims (3)

a) a measuring means for irradiating a blood sample with light to measure the amount of scattered light from the blood sample;
b) Coagulation that obtains a scattered light amount value measured by the measuring means at a predetermined time interval and detects a coagulation end point based on a change over time in the scattered light amount value after a predetermined reagent is added to the blood sample. End point detection means;
c) The point at which the amount of scattered light reaches 1 / N (N is a predetermined value of 1 or more) of the amount of scattered light at the end point of coagulation is defined as the freezing point, and the elapsed time from the point of addition of the reagent to the coagulation point is defined as the coagulation time. A coagulation time calculating means for calculating;
d) determining means for determining whether the coagulation time is normal;
e) When the determination means determines that the coagulation time is normal, the measurement by the measurement means is terminated; otherwise, the measurement by the measurement means is continued and after the start of the continuous measurement Assuming that each time point is the end point of coagulation, the calculation of the coagulation time by the coagulation time calculation unit and the determination by the determination unit are sequentially executed, and if the determination unit determines that the coagulation time is normal, Control means for terminating the measurement by the measuring means;
A blood coagulation analyzer characterized by comprising:   When the rising of the scattered light amount is confirmed during execution of the continuous measurement, the control means restarts the detection of the coagulation end point by the coagulation end point detecting means, whereby the coagulation end point is determined after the start of the rise. 2. The blood coagulation analyzer according to claim 1, wherein if detected, the calculation of the coagulation time by the coagulation time calculation unit and the determination by the determination unit are executed.   The blood coagulation analyzer according to claim 1 or 2, wherein the determination means determines whether or not the coagulation time is normal from a combination of the amount of scattered light at the coagulation point and the coagulation time.

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