Evaluation of a new blood cell counter with sheath flow system.

A blood cell counter with a sheath flow system has been developed to eliminate the drawback of the Coulter type blood cell counter, namely, signal distortion caused by the cells passing through the electric aperture gate. With the new system, signal distortion was low and a near-normal distribution curve for erythrocytes and resin particles was obtained. The counter has a computer program for determining the red cell distribution width, which represents an actual size difference at 20% of the relative frequency of the distribution curve. This is independent of mean cell volume, and is considered to be of clinical importance. We examined the values in 2,300 healthy subjects and patients with various hematological disorders.