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 alpha-thalassemia minor, and 10 with presumptive iron deficiency. Of the 54 people with microcytic (MCV less than 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 greater than 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.