Hematologic findings in Southeast Asian immigrants with particular reference to hemoglobin E

Recent immigrants from Southeast Asia were screened for hematologic abnormalities using a multichannel cell counter (Coulter S), peripheral smear, free erythrocyte protoporphyrin (FEP), isoelectric focusing, and a qualitative screen for glucose-6-phosphate dehydrogenase deficiency. Hematologic abnormalities were further defined by hemoglobin electrophoresis, globin electrophoresis, HbA₂ levels, and HbF levels. Of the 189 adults studied, 68 (36 percent) were hematologically abnormal, including 28 hemoglobin E (HbE) heterozygotes, six HbE homozygotes, 14 with α-thalassemia minor, and 10 with presumptive iron deficiency. Of the 54 people with microcytic (MCV <80fl) red blood cells (RBC), 52 had evidence of HbE or thalassemia and two had iron deficiency alone; five had both iron deficiency and a hemoglobinopathy. Homozygosity for HbE results in an asymptomatic condition similar to thalassemia minor with microcytic RBC, large numbers of target cells, normal or slightly reduced hematocrit and >90 percent HbE. People heterozygous for HbE are asymptomatic and have hematologic findings similar to thalassemia minor with slightly reduced or low normal MCV and 25 to 35 percent HbE.