High performance liquid chromatography (HPLC) as a screening tool for classical Beta-thalassaemia trait in malaysia.

UNLABELLED: Beta-thalassaemia is characterized by a decrease (β(+)) or absence (β(0)) in the synthesis of β-globin chains of human haemoglobin. The heterozygous state for β(+) or β(0) result in β-thalassaemia trait in which the hallmark is the presence of an elevated level of Haemoglobin (Hb) A(2) (α(2)δ(2)). In the past, the traditional methods such as cellulose acetate electrophoresis with elution and microcolumn chromatrography have been the techniques used by the majority of the laboratories in Malaysia for the estimation of (Hb) A(2) levels. The recommended method currently is high performance liquid chromatography which has only been introduced in a few laboratories in the country.

AIM OF THE STUDY: To determine the cut-off level for (Hb) A(2) when estimated by high performance liquid chromatography (HPLC) in the diagnosis of classical beta-thalassaemia trait, a condition in the homozygous state that results in beta-thalassaemia major and red blood cell transfusion dependency.

RESULTS

High performance liquid chromatography (HPLC) as a method for the measurement of (Hb) A(2) was rapid, and technically easy. A cut-off level of (Hb) A(2) >4.0 % predict the majority of carriers of classical beta-thalassaemia.

CONCLUSIONS

A full blood count (FBC), together with red blood cell indices generated on an automated blood counter in conjunction with the measurement of Hb A(2) on the VARIANT-BioRad, an automated HPLC machine and the beta-thal short program is an appropriate approach for the screening and presumptive identification of carriers of classical beta-thalassaemia prior to DNA studies for definitive diagnosis. In carriers for classical beta-thalassaemia, the MCV and MCH are <75 fl and <27 pg respectively with a Hb A(2) cut-off level > 4.0% [range 5.9 (4.5-8.1)] on the VARIANT-BioRad.