Cell Counter, Blood

This article discussed the basic principles of hematology with emphasis on humans. Enumeration of cell population distribution in peripheral blood is examined using optical, electrooptical and light scattering techniques. As seen, such experimental modalities can be automated and the resulting hematology analyzers can be used for clinical application. Even though the exact strategy of cell counting varies between various manufacturers of automated cell counters, performance standards for such instrumentation have been established by the National Committee for Clinical Laboratory Standard (NCCLS) and the International Council for Standardization in Hematology (ICSH). The parameters evaluated here include (1) accuracy in measurement within a single batch and between batches of blood samples; (2) carryover of parameters between consecutive samples; (3) linearity or the ability to get similar measurements when the sample is diluted to different levels before being read; and (4) clinical sensitivity or the specificity and efficiency with which flags are generated during analysis to detect abnormal readouts.