GSTM1 and hemoglobinopathy: The “Hb defect” flag performed poorly when it was specifically used to detect a homozygous EE disorder, as compared with when it was used to detect “any” hemoglobinopathy, as well as when it was used to detect any of the other hemoglobinopathies (α-thalassemia, heterozygous AE, and coinherited α-thalassemia/heterozygous AE).