Nova Celltrak, Inc.

Richard A Carlson

Henry R Angel

James W Hennessy

An apparatus for making blood counts is provided with computer and instrument control to optimize performance of the apparatus. Means for counting blood cells such as platelets, white blood and red blood cells enables a plot of the number of particles counted in each of the adjacent bands or channels inclusive within a selected range of particle size so that a plot of count against particle size may be made. The computer enables analyses of plots thus obtained by system algorithms in order to correct errors of various types which may occur in the plot. For example, by calculating the logarithms of the counts of particles and of mean particle size for each particle size channel, a further plot of log count against log of blood particle size of generally symmetrical bell shape may be generated. The computer further calculates change of logarithm (.DELTA. log) of counts in adjacent channels. A straight line of fixed slope is then plotted representing the change of logarithm counts against the logarithm of blood particle size, giving more weight to those points near the peak. The calculation steps are reversed using the points on the straight line for ultimately calculating counts in the various channels from .DELTA. log and taking the anti-log of the log particle size to regenerate a new curve showing more accurately distribution of the selected blood particles against particle size.

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Meriden, CT, United States of America

Richard A Carlson