Interpretation of Electronically Determined Macrocytosis

doi:10.1059/0003-4819-78-5-677

Interpretation of Electronically Determined Macrocytosis

New Haven, Connecticut

Abstract

Macrocytosis identified by electronic erythrocyte sizing equipment is clinically significant whether anemia is present or not. Half of all patients with marked macrocytosis (mean corpuscular volume of 115 µm³ or greater) identified in a hospital hematology laboratory had deficiency of folic acid or vitamin B₁₂, or both, as defined by erythrocyte folate and plasma B₁₂ measurements. The proportion of deficient patients increased with increasing degrees of macrocytosis. Of patients without deficiency, half had liver disease or alcoholism with probable liver disease. Screening patients with marked macrocytosis for deficiency of folic acid and vitamin B₁₂ has a high diagnostic yield and has become a routine procedure in our laboratory.

Article and Author Information

▸From the Departments of Laboratory Medicine and Internal Medicine, Yale University School of Medicine; and the Clinical Microscopy Laboratories, Yale-New Haven Hospital; New Haven, Connecticut.
Grant support: 5T01GM00696 and HE 05316-12, U.S. Public Health Service.
▸Requests for reprints should be addressed to Peter McPhedran, M.D., Yale-New Haven Hospital, 789 Howard Ave., Room 142 MU, New Haven, CT 06504.
- Received November 9, 1972.
- Accepted December 21, 1972.