Lymphocyte percentage and counts provided by Coulter Counter S+II: comparison with optical method and three automatical leukocyte analyzers (Hemalog D, H 6000, Diff 3).

The Coulter Counter Model S+II is an automatic analyzer designed to measure the routine hematological parameters and to carry out distribution curve analysis of platelets, erythrocytes and leukocytes. The leukocyte histogram analysis is used as a basis for calculation of both lymphocyte percentages and absolute counts. In this study, we compared the differential count obtained by light microscopy studies of 2355 blood smears with the percentage of lymphocytes in the leukocyte population as determined by the S+II. A comparison was also performed between the S+II and Hemalog D, H 6000, and Diff 3 System on a smaller sample number. There was a good correlation between lymphocyte percentages and counts given by the S+II and other methods. Furthermore, reproducibility studies, performed with the Coulter Counter Model S+II, suggested that the lymphocyte percentage given by this instrument was accurate, except for extreme values. Lack of calculation of lymphocyte parameters by the instrument was often found to correspond to spontaneous platelet aggregation and/or to abnormalities of differential counts. It is suggested that lymphocyte analysis provided by the S+II may be used as a basis for a new approach to white blood cell (WBC) analysis, which could exclude differential counts in most routine cases.