Hemoglobin E: another cause of microcytic anemia in North America.

The influx of Southeast Asians has expanded the differential diagnosis of microcytic, hypochromic anemia in this country. We describe four patients with hemoglobin E, all of whom had microcytic, hypochromic anemia. Hemoglobin E is benign in both the heterozygous and homozygous states. On routine hemoglobin electrophoresis at pH 8.4, hemoglobin E will migrate near the hemoglobin C and hemoglobin A2 regions. If hemoglobin E is suspected, the laboratory should be advised to do electrophoresis on citrate agar at pH 6.3.