Abstract: A system that is particularly useful in biological fluid analysis includes a face plate member and a mating flexible member, one of which has a plurality of passages. Selected motion of the flexible member provides a valving action to control fluid flow into, through, and out of the passages. An analysis chamber in a surface of the face plate member is in fluid communication with a passage and has an analyzer which, for a hematology analyzer, is preferably an impedance-type particle counter.

Abstract: In a hematology measurement apparatus, a hematocrit value is generated by incrementing a value in accumulation means in accordance with measured sizes of red blood cells. The hematocrit value is corrected for coincidence by incrementing the value additionally in response to the production of red blood cell count coincidence corrections pulses.

Abstract: A method and apparatus for correcting the output count of an electronic particle counting system in which additional correction pulses are added to the pulses generated by the electronic counting system as a result of detecting particles flowing through an orifice. The correction pulses are added in accordance with a curve which is generated by statistical computation determined by the size of the orifice and the character of the particles being detected therein and their quantity per unit volume. The improved apparatus comprises the addition of a second counter chain to the system which includes digital counters having outputs at various frequencies which are dividends of the frequency of the input pulses. The various-frequency outputs are combined through logic circuitry to generate individual correction pulses at frequencies such that when the pulses are added to the detected pulses, the total of the pulses corresponds to the actual number of particles flowing through the orifice.