The α-thalassemia-1 (α-thal-1) Southeast Asian ( SEA ) type deletion, β-thalassemia (β-thal) and Hb E [β26(B8)Glu→Lys, GAG > AAG] are the most common genetic disorders in Southeast Asian populations. Mean corpuscular volume (MCV) < 80.0 fL with normal hemoglobin (Hb) is used for screening α- and β-thal, and a Hb E level of less than 25.0 is used for predicting α-thal-1 in Hb E trait. Thus, levels of Hb, MCV and Hb A2/E were reviewed and compared between the SEA type deletion co-inherited with β-thal trait (n 61), with Hb E trait (n 102) or homozygous Hb E (n 13) and β-thal trait (n 636), Hb E trait (n 544) or homozygous Hb E (n 83), respectively. When comparing the values of all three analyzed hematological parameters, only the SEA /β E values were shown to be significantly lower than those of Hb E trait. Furthermore, at a cut-off value of Hb A2/E of 21.54, 95.0 of the SEA /β E had Hb A2/E levels lower than this cut-off value, while 94.0 of Hb E trait had Hb A2/E at higher levels. Accordingly, the Hb A2/E level at 21.54 is the best indicator for predicting co-inheritance of the α-thal-1 SEA / deletion and Hb E trait. © 2012 Informa Healthcare USA, Inc.