Quantification of haemoglobin A2 for mass screening of major haemoglobinopathies

Abstract

Haemoglobinopathies are the most prevalent single-gene disorders and include a wide range of disorders most commonly thalassaemia and sickle cell disease (SCD). Multiple screening methods to diminish morbidly and mortality of those suffering with haemoglobinopathies have been developed including HPLC and ion-exchange microcolumn chromatography. Due to significant shortcomings upon use of these techniques, many studies in search of better screening strategies to quantifying HbA2 levels in mass populations screening have been conducted. The aim of this review is to compare and contrast three methods for quantifying HbA2 to ultimately find a more effective protocol than standard methods for mass screening of major haemoglobinopathies. Alternative HbA2 quantification protocols for mass screening established by Shihabi et al., capillary zone electrophoresis (CE) in arginine-Tris buffer, Daniel et al., MS/MS, and Kuntaruk et al., sandwich ELISA, were analysed and compared. Upon comparison, differences in interfering factors which effect successful separation of haemoglobin and quantification of HbA2 were noted whereby sandwich ELISA was deemed better than CE and MS/MS for quantifying HbA2 due to its high specificity. Moreover, comparison of the techniques with standard methods of HPLC and micro-column chromatography noted that both MS/MS and CE are better options for detecting Hb Lepore when compared to sandwich ELISA. To conclude, since ideally the selected method must be applicable for both neonatal and adult screening, then the most effective protocol forscreening major haemoglobiopathies in mass populations is MS/MS.