An evaluation of the Coulter Diff3 50, an automated differential leukocyte counter.

The Coulter Diff3 50 analyzes Wright stained films using computerized pattern recognition. It is capable of reporting on the differential leukocyte count, red cell morphology, platelet sufficiency and the reticulocyte count. Although the precision of the differential leukocyte and reticulocyte counts is better than that of the manual method, correlation is poor and monocyte classification is a major problem. The Diff3 50 is useful for examining relatively normal films and for follow-up counts, but in our experience it has proven more unreliable and costly than expected.