Separation of haemoglobin HbE and HbA by the fully automated, high-pressure liquid chromatography Tosoh HLC-723 G7 analyzer.

High-pressure liquid chromatography instruments specifically devised for separating haemoglobin (Hb) fractions have been increasingly employed by the hospital laboratories over the recent years since they allow easy and fast screening for several Hb variants. Although such instruments may be proposed as sensitive, specific and reliable alternatives to the classic electrophoretic techniques, a major drawback of this screening strategy is the almost identical retention time of several Hb variants. In particular, at least 18 Hb variants have been reported in the same retention window as HbA(2), including HbE, the second most common beta-chain variant in humans after sickle cell trait. Recently, we evaluated the performance characteristics of an improved buffer formulation originally conceived for Hb variants separation procedures on the fully automated high-pressure liquid chromatography instrument Tosoh G7. At variance with other fully automated high-pressure liquid chromatography analyzers, the elution pattern on the G7 in subjects heterozygous for HbE is characterized by the presence of four suggestive peaks (HbF, HbA, HbA(2) and HbE), confirming the effective separation of HbE from HbA(2). Because of its potential value in the diagnosis of the thalassaemia syndromes, the effective separation of HbA(2) from HbE can provide clinical laboratories with a valuable information for the diagnostic reasoning.