Patent ID: 8227250

Claim:
A cartridge for counting and discriminating a plurality of types of blood cells in a blood sample in one counting operation, comprising a housing with a first liquid storage chamber that has prestored therein a lysing reagent that lyses erythrocytes while maintaining counting ability of other blood cell types, wherein the lysing reagent contains a surfactant comprising a saponin, or wherein the lysing reagent comprises a quaternary ammonium salt and further comprises N-(1-acetamido)iminodiacetic acid to further assist the quaternary ammonium salt in minimizing debris stemming from hemolysed red blood cells, a first mixing chamber and a first collection chamber separated by a wall containing a first orifice for the passage of the cells between the first mixing chamber and the first collection chamber, a first cell characterizer that characterizes and counts the plurality of types of blood cells passing through the first orifice, the first cell characterizer including respective electrodes in the first mixing chamber and the first collection chamber, a bore in the outer surface of the housing for entrance of the blood sample, and a first sampling member positioned in the housing for sampling the blood sample and having a first cavity for receiving and holding the blood sample, the first sampling member being movably positioned in relation to the housing in such a way that in a first position, the first cavity is in communication with the bore to receive and hold the blood sample, and in a second position, the first liquid storage chamber communicates through the first cavity with the first mixing chamber so that the blood sample held in the first cavity can be flushed with the lysing reagent prestored in the first liquid storage chamber into the first mixing chamber and mixed with the lysing reagent in the first mixing chamber.