Problems in microscopic and automatic cell differentiation of blood and cell suspensions

Problems in microscopic and electronic differential cell-counting of blood and cell suspensions were studied. Smears made from peripheral blood by the spreading technique or by the spin-slide technique did not show skewed cell distribution. The automatic differential cell counter Hemalog D was better than microscopy for basophils and showed satisfactory results compared with microscopy for polymorphonuclear neutrophil granulocytes, lymphocytes and eosinophils, while there was some disagreement for monocytes. Hemalog D, which includes blasts in large unstained cells (LUC), showed LUC in 95% of our patients, while blasts were found only in 4% by microscopy. The commonly used methods for preparing smears from cell suspensions showed markedly skewed cell distribution, which was avoided by an improved technique for cytocentrifugation, by a spin-slide technique and by a spreading technique resembling that used for blood.