Hyperglycemic macrocytosis in electronically determined mean corpuscular volume. Use of three different automatic cell counters.

Spurious macrocytosis in electronic cell counters has been associated with hyperglycemia. The increased mean corpuscular volume (MCV) is thought to be secondary to osmotic disequilibrium between the erythrocyte and the diluent used in the automatic cell counters. Employing three different hematology cell counters, the effects of increasing concentration of glucose (400 mg per dl to 2000 mg per dl), at different temperatures and after various incubation periods were studied. In addition to macrocytosis being temperature and glucose concentration dependent, the magnitude of cell size variation also depends on the type of instrument used.