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November 28, 1977

Microcytic Polycythemia: Frequency of Nonthalassemic Causes

Author Affiliations

From the Department of Medicine, University of Southern California School of Medicine, and the Los Angeles County—University of Southern California Medical Center, Los Angeles. Dr Bessman is now with the Johns Hopkins Medical Institution, Baltimore.

JAMA. 1977;238(22):2391-2392. doi:10.1001/jama.1977.03280230055022

A high RBC count combined with a low mean volume generally is attributed to thalassemia minor, either a or β, or to polycythemia vera with iron deficiency. Among 330 patients with a mean corpuscular volume (MCV) less than 70 cuμ, 35 had increased RBC counts. Of these, 26 had thalassemia minor and four had polycythemia vera. Five had secondary polycythemia (four from hypoxia, one from hypernephroma) with incidental iron deficiency. In the four of these patients given iron, the RBC count remained above normal and the MCV rose to normal. The RBC size distribution curves reliably distinguished between thalassemia minor and polycythemia with iron deficiency.

(JAMA 238:2391-2392, 1977)