JPH0226175B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for counting individual particles suspended in a liquid, particularly individual blood cells in blood, for various measurements and tests.

In this type of device, abnormal situations that may occur during particle detection operation include particles or dust adhering to the vicinity of the detection pore, changing the wave height or waveform of the detection signal, or For example, the detection operation may not be performed due to complete blockage, or the detection operation may not be performed accurately for the target type of particle due to incomplete pre-treatment of the sample.

Conventionally, methods for detecting particles adhering to the vicinity of a detection pore include (1) a method of detecting when the time required for a predetermined volume of sample to flow through the pore is longer than expected; ) A method for detecting changes in the current when no particles are passing through the pore, (3)
There are methods such as (4) detecting a change in the waveform by analyzing the output signal waveform including the particle detection output, and (4) detecting when the pulse interval of the particle detection output becomes longer than a set value.

Among these methods, method (1) requires a simple configuration that only measures the time required from the start to the end of the particle detection operation, but on the other hand, it may cause slight sample passage obstruction or temporary passage obstruction. There is a drawback that it cannot be detected in cases where spontaneous recovery occurs later. Method (2) requires sampling the steady current between the particle detection signals, so the signal interval may be short, a lot of noise may be mixed in, or the amplitude of the particle detection signal may be affected. This method is difficult to implement in cases where a large number of particles has a long tail, and the device has the drawback of becoming complicated. In addition, method (3) memorizes the pattern of the normal particle detection signal,
This method detects deviations by comparing the pattern of the newly appeared particle detection signal, and has the advantage of being able to distinguish between noise and other types of particles, but the configuration of the device is significantly more complicated. There is a drawback. Furthermore, in method (4), the particle detection output appears randomly, so the pulse interval may be quite long even during normal operation, and in addition, the number of blood cells in the blood of an anemic patient decreases to a fraction of that. Considering that the pulse interval of the particle detection output will be several times larger due to this, if the setting is set so that false alarms will not occur during normal operation, there is a drawback that it will not be possible to sufficiently detect the occurrence of abnormal situations. .

This invention has a relatively simple configuration and is capable of accurately detecting passage obstacles without being affected by noise, etc., and also detects inaccurate measurements due to incomplete pre-treatment of the sample. This will be explained based on an example.

In FIG. 1, reference numeral 1 denotes a sample obtained by diluting blood with physiological saline, for example, and is accommodated in a beaker 2, into which a detector 4 having a detection pore 3 is immersed. Electrodes 5 and 6 are immersed in the sample in the detector 4 and the beaker 2, respectively.
A predetermined amount of the sample 1 inside is aspirated into the detector 4 through the pore 3 by the quantitative suction device 7 .

The resistance change in the current path in the sample from the electrode 5 through the pore 3 to the electrode 6 is detected by the detection circuit 8, and only the one with the required amplitude passes through the threshold circuit 9 and is sent to the counting circuit 10. Given. Counting circuit 10
In response to a signal emitted by the quantitative suction device 7, the counting operation is started when the quantitative suction of a specified amount of the sample is started, and the counting operation is stopped when the quantitative suction of the specified amount of the sample is completed.

Reference numeral 11 denotes a conversion circuit that obtains a voltage proportional to the pulse counting rate (pulse rate) of the pulses supplied to the counting circuit 10, which shapes input pulses into pulses with a constant amplitude and time width, as shown in FIG. 2, for example. It consists of a monostable multivibrator 12 and a constantly discharge type integrating circuit 13 that obtains a voltage proportional to the counting rate of the shaped pulses. The monostable multivibrator 12 preferably has an output pulse width of about 10 to 50 μS. In addition, the time constant determined by the resistor R and capacitor C in the performance distribution circuit 13 must be such that even if output pulses of the above width are input at intervals of about 300 μS, no ripples will occur in the output voltage. is desirable.

The output voltage of the conversion circuit 11 is determined by the changeover switch 14.
is stored in the voltage holding circuit 15 via the a side of the switch 14, and is stored in the comparator circuit 16 via the b side of the changeover switch 14.
Here, the voltage is constantly compared with the storage voltage of the voltage holding circuit 15. The changeover switch 14 is normally connected to the b side, but is temporarily switched to the a side by the counting start signal issued by the quantitative suction device 7, and the voltage holding circuit 15 changes the pulse counting speed to be counted at that time. to be memorized.

The comparator circuit 16 is connected to the input voltage of the voltage holding circuit 15.
When the voltage changes by more than a certain limit compared to the stored voltage, an output is generated, and this output is given to the alarm circuit 17 and causes the alarm sound generator 18 to generate an alarm sound. The output of the comparator circuit 16 is also applied to a display 19 that displays the count value of the counting circuit 10 to indicate the occurrence of an abnormal situation. Note that 20 is a monitor cathode ray tube circuit for observing the pulses to be counted.

In the above-described apparatus, when the quantitative suction device 7 is started, the sample in the beaker 1 begins to be sucked into the detector 4 through the pore 3. Each time a particle passes through the pore 3, a pulse-like impedance change occurs between the electrodes 5 and 6, and this change is detected by the detection circuit 8, and then passed through the threshold circuit 9 to generate a counted pulse of a certain wave height or higher. Only the second one goes to the counting circuit 10. The pulses to be counted can be observed by the monitor cathode ray tube circuit 20.

When the quantitative suction device 7 issues a counting start signal, the pulses to be counted are counted in the counting circuit 10.
Then, when the suction amount of the metered suction device 7 reaches a predetermined amount from the time when the counting start signal is issued, a counting end signal is issued, and the count value of the counting circuit 10 at that time is displayed on the display 19.

On the other hand, the counting speed of the pulses to be counted at the time when the counting start signal is issued is stored in the voltage holding circuit 15, and the counting speed of the pulses to be counted thereafter is always compared with this stored value in the comparator circuit 16. Here, when particles etc. adhere to the periphery of the pore 3 and its effective opening area is reduced, the counting speed of the pulses to be counted decreases, and when the pore 3 is completely blocked, the counting speed becomes zero. Become. Furthermore, if noise is mixed into the pulses to be counted for some reason, the counting speed increases. Therefore, when such a situation occurs, the comparator circuit 16 produces an output, the alarm sound generator 18 emits a sound, and the display 19 displays an indication.

When counting the number of white blood cells, sample 1 is prepared by adding a hemolytic agent to dissolve red blood cells. At this time, if the standing time is too short or the stirring is insufficient, both the remaining red blood cells and white blood cells are counted at the beginning of counting, but the number of red blood cells counted changes as time passes. Even when a change in counting speed occurs due to such a cause, the above-mentioned alarm sound is generated and displayed.

As described above, although the present invention has a simple configuration, it can accurately detect failures due to particles adhering to the detection pores, changes due to incomplete pre-treatment of the sample, etc. It is possible to prevent erroneous measurements that may have been overlooked because the count value is not significantly different from the normal value, and improve the reliability of the measurement.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of this invention;
The figure is a circuit diagram of the conversion circuit 11 in the same embodiment. 1... Sample, 2... Beaker (container), 3... Detection pore, 4... Detector (container), 5 and 6...
electrode (impedance change detection means), 7... quantitative suction device, 10... counting circuit, 11... conversion circuit, 15... voltage holding circuit, 16... comparison circuit.

Claims (1)

[Claims] 1. Two containers containing suspended liquid samples, a detection pore communicating between the containers, means for transferring a predetermined amount of the sample from one container to the other container through the pore, and the above-mentioned means for detecting a change in impedance of the sample in the pore;
In a particle counting device having a counting circuit that counts the frequency of change in impedance, a conversion circuit that obtains a counting speed signal of the change in impedance, and a circuit that stores the counting speed signal at the time when the counting operation of the counting circuit starts. a comparator circuit that compares the counting speed signal that appears thereafter with a value stored in the storage circuit and generates an output when the difference exceeds a certain limit; and a device that issues an alarm or display based on the output of the comparator circuit. An abnormality alarm device in a particle counting device, characterized in that it has the following.