Blood analyzer and blood analyzing method for classifying white blood cells

A blood analyzer, comprising:

• a sample preparing part comprising a first chamber for preparing a first measurement sample comprising blood, a hemolyzing reagent, and a staining reagent and a second chamber for preparing a second measurement sample comprising blood and a diluent;
• a first detection unit comprising a flow cell in which the first measurement sample flows, a light source for irradiating the first measurement sample flowing in the flow cell, a PIN photodiode for detecting a side scattered light from the first measurement sample irradiated by the light source, and an avalanche photodiode for detecting a side fluorescence light from the first measurement sample irradiated by the light source;
• a second detection unit comprising a second flow cell in which the second measurement sample flows and electrodes that detect changes of direct current resistance therebetween caused by the second measurement sample flowing therebetween;
• a signal processing part configured for processing a side scattered light signal from the PIN photodiode, a side fluorescent light signal from the avalanche photodiode and a third detection signal from the electrodes, the signal processing part comprising:
• gain-adjustable amplifiers configured to amplify the side scattered light signal and the side fluorescent light signal respectively at gains adjustable according to measurement modes, including a white blood cell classifying mode and a reticular red blood cell measurement mode;
• low pass filters configured to reduce high frequency noise included in the side scattered light signal and the side fluorescent light signal amplified by the gain-adjustable amplifier wherein;
• high pass filters configured to reduce fluctuations of base lines of the side scattered light signal and the side fluorescent light signal filtered by the low pass filters;
• and
• base line adjusters configured to adjust the base lines of the side scattered light signal and the side fluorescent light signal filtered by the high pass filters to a predetermined level;
• and
• an analysis part configured for classifying white blood cells in the first measurement sample into at least four groups, comprising neutrophils, lymphocytes, monocytes, and eosinophils, based solely on the side scattered light signal and the side fluorescent light signal processed by the signal processing part, and for counting red blood cells in the second measurement sample based on the third detection signal processed by the signal processing part.