The effect of smudge cells on leukocyte counting--are chamber counts necessary?

Leukocyte counts obtained in the Coulter Model S and Model F were compared with counts from hemocytometers and estimates from peripheral blood smears from 38 patients with increased numbers of smudge cells associated with chronic lymphocytic leukemia, with leukemias other than chronic lymphocytic leukemia, and without leukemia. The results indicate no method-dependent pattern of count loss. Cell counts were not related to the number of smudge cells present; the number of smudge cells were unrelated to the nature of the patient's disease state. We conclude that in the presence of smudge cells, leukocyte counts can be made as reliably by automated methods as by pipette and chamber technics. This conclusion is at variance with what has been previously reported. Although the basis for this discrepancy is not clear, it may be related in part to differences in the formulation of the lysing agents used.