Computerized calculation of platelet counts obtained with particle counters

Three mathematical manipulations of raw data are necessary in order to use a small programmable calculator to compute platelt counts obtained with particle counters. Two of these manipulations use constant parameters and are easily incorporated into programmable calculators, which are in use in many laboratories. The third is a correction fro the excess concentration of platelets in supernatant plasma that results from sedimentation of red cells; it requires a large table of correction factors. This table often exceeds the storage capability of programmable calculators, and mathematical approximation is necessary. Two methods for close approximation of the table were developed by using a cosine function and a third order polynomial function of the hematocrit value.