Leukocyte differentials. Are they worth the effort?

This article explores the analytical inaccuracies of routinely performed leukocyte differentials and cites the known biologic and personal physiologic variability in the total leukocyte counts and the leukocyte differential. The clinical value of leukocyte differentials in patients without hematologic disease is assessed on the basis of reports in the existing medical literature. It is concluded that the 100- or 200-cell differential is of no value in the majority of patients on whom the test is requested and that an initial scan of 300 or more cells in concert with the 10,000-cell differentials now available from instruments will soon replace the traditional " diff ".