Count accuracy control means for a blood analyses system

The method of approximating curve shape in a blood particle log normal size distribution curve comprising:

• analyzing a blood sample using a cell counter to count blood particles within each adjacent channel of blood particle size over at least a predetermined range of particle size,
• calculating the logarithm of the count of blood particles for each particle size channel, enabling plotting a log count vs. log particle size distribution curve of generally symmetrical bell shape,
• calculating change of logarithm (.DELTA.log) of counts in adjacent channels and the logarithm of blood cell input amplitudes,
• using the least squares fit formula to generate a straight line representing change of logarithm (.DELTA.log) of counts in adjacent channels vs. the log of cell particle size in said channels, the straightness of which line permits examining the log curve for its uniformity, and
• determining if the curve does measure up to predetermined minimum requirements, and if not, using measured data to generate the cell count for each cell size between two predetermined threshold limits.

In a blood cell counting apparatus employing a computer, the method of assuring more accurate results comprising:

• analyzing a blood sample using a cell counter to count blood particles within each adjacent channel of blood particle size over at least a predetermined range of particle size,
• computing a projected count for each particle count channel,
• making a periodic check of intermediate counts at predetermined intervals during each count to generate periodic results,
• comparing the periodic results with said projected counts and
• if any of the intermediate results deviate from the projected count, rerunning the test.