Investigation on the automatic cell counting in feline blood

The usability of the haematology analyzers ''F-800'' and ''System 9000+'' was investigated in cats using 40 blood samples. Reference measurements were done with a haemocytometer or the microhaematocrit method. Reliable leukocyte counts were measured with the analyzer F-800 in cases only, when the histogram rendered possible a clear demarcation of the leukocyte curve (r = 0.97, n = 25). With the analyzer System 9000+ a changed basic adjustment of the inferior discriminator (49 fl) vouched for a close correlation with the values measured visually (r = 0.94). The volume distribution curves of the erythrocytes and thrombocytes which were partly overlapping allowed an approximate counting of the thrombocytes with both analyzers only of one half of the samples, The inaccuracy resulting from the inexact separation had only a relatively unimportant effect on the automatically measured erythrocyte count due to the numerical relation of erythro- and thrombocytes. Hereat a close correlation to the haemocytometer method (r = 0.95) was found as well as slightly higher values with the automatic counting. The haematocrit measured with the analyzer F-800 and to a smaller extent by the use of the System 9000+ lay distinctly higher in relation to the Values measured by microhaematocrit, when the analyzers were calibrated with human standards. Besides a species specific calibration of the haematocrit and a particular basic adjustment for leukocyte counting with the analyzer System 9000+, the use of the investigated haematology analyzers on feline blood requires an individual estimation of the histograms and removing of the discriminators as well as frequently a repetition of the leukocyte- and thrombocyte counting with a haemocytometer.