RESUMO
The human platelet volume distribution has been shown log-normal. Coulter Counter S-Plus models, as well as JT and STKS models, give mean platelet volume and platelet distribution width parameters. A computerized mathematical method, working with an IBM-XT microcomputer, was designed to calculate median and modal volumes, as well as the percentage of platelets smaller or larger than operator definable volume thresholds, on the basis of mean platelet volume and platelet distribution width. Preliminary experiments defined that the optimal stability of results was obtained in the range 2-6 hours after the blood collection; further experiments demonstrated that the results of the mathematical analysis were reproducible and accurate, by comparison to data obtained from a channel analysis in all samples, even including macroplatelets and/or microplatelets. It was thus shown that Coulter counters working with a curve fitting process may provide a complete analysis of platelet distribution curves, which could be extensively used for studying pathological conditions involving changes in platelet parameters.