RETICULOCYTE COUNTS IN LABORATORY-ANIMALS USING A MANUAL AND A FLOW CYTOMETRIC PROCEDURE (SYSMEX R-3000(TM))

An evaluation of the flow cytometric procedure for reticulocyte counti ng was performed, together with a comparison to a reference manual cou nting method. An automated reticulocyte analyser, the Sysmex R-3000(TM ) (Flow cytometric auramine O methods) was used to enumerate the absol ute reticulocyte counts and the percentage of reticulocytes in blood o btained from rats, dogs and monkeys. Simultaneously, a maturation dist ribution was obtained by subdividing the reticulocytes into three matu ration classes according to their fluorescence intensity. The reticulo cyte counts and the maturation distributions can be determined rapidly and easily. The coefficients of variation (CV) for the within-day pre cision study in the reticulocyte counts of the three species were foun d to be 9.7%-20.5% for the microscopic method and 4.4%-9.4% for the fl ow cytometric method. A very good correlation was observed between the microscopic count and flow cytometric methods (r = 0.958). In conclus ion, because of high reproducibility and good agreement with the manua l counting method for these species, flow cytometric analysis of retic ulocytes is an attractive alternative procedure to microscopic enumera tion in toxicological studies.