[Evaluation of the Coulter Counter S+IV LMG: estimation of the leukocyte formula. Comparison with microscopic methods].

The evaluation of a differential count instrument of the Coulter S+line, the S+IV LMG Coulter-Counter, in particular for the lymphocyte, monocyte and granulocyte count was carried out. This differential analysis was compared with more classical methods of the manual (microscope) or automatic type (image analyser, Hematrack 360 type, Geometric Data). The repeatability is very good and the correlations excellent. The instrument can even detect the presence of low percentages of abnormal cells. Placement of reagents and samples at room temperature is important and the samples can be kept at room temperature for at least 9 hours without disturbing the count. In addition, energetic shaking of the samples does not change the count for the three types of cells. Due to the alarms given by the instrument as regards the cell distributions and all of the parameters of the blood cell count, no pathology should be ignored. In their laboratory, the authors note that about 25% of the smears are further examined by microscope.