Increased electronic mean corpuscular volume induced by marked hyperglycemia.

A very high glucose level in a diabetic was associated with an increased electronic mean corpuscular volume (MCV). The hematocrit was falsely high and the mean corpuscular hemoglobin concentration (MCHC) falsely low, while the mean corpuscular hemoglobin (MCH) was normal. Blood smears failed to corroborate the abdominal indices. Correct values could be obtained by predilution of the blood in isotomic medium and allowing 10 to 15 minutes for equilibration. It is suggested that glucose in the cell produces a hyperosmolar state which results in the rapid diffusion of water into the cells in the counter. The phenomenon is dependent on the concentration of glucose to which the red cell is exposed. It is temperature dependent and it is rapidly reversible.