Hemoglobin (Hb) A 2 electrophoresis has been used for prenatal screening for the ß-thalassemia trait (ßTT). We retrospectively reviewed Hb capillary electrophoresis performed in our laboratory. We found that of the 122 cases showing elevated HbA 2 levels, 79 cases were due to hemoglobinopathies, mostly HbS. Review of the RBC indices suggested that 3 of 36 cases with elevation of HbA 2 in the HbAA-pregnancy group had ßTT and 29 had normal RBC indices; data were not available for 4 patients. Among 7 cases with elevation of HbA 2 in the HbAA-other group, 5 had ßTT and 2 were normal. The number of patients without ßTT but with HbA 2 elevation in the pregnant group was significantly higher than that in the nonpregnant group. When a higher HbA 2 cutoff (3.5%) was used, only 3 pregnant patients without ßTT had HbA 2 elevation, similar to the nonpregnant group. We found that a significant number of pregnant women with mild HbA 2 elevation had no evidence of ßTT, compared with the nonpregnant group. © Society for Clinical Pathology.
