Evaluation of an immunochromatographic test for alpha thalassaemia screening in a multi-ethnic population

The standard screening method for alpha thalassaemia is the examination of HbH preparation. It is labour intensive and poorly standardized. The development of a rapid strip immunochromatographic test (ICT) for haemoglobin Barts offers a fast, user friendly and cost-effective alternative screening tool.

A total of 180 subjects with results of the thalassaemia screen and genetic testing were included. Results of the ICT and HbH preparation were correlated with genetic results to determine the performance characteristics of the tests and the effect of mean sample age on results.

Of 180 subjects, 111 carried alpha thalassaemia mutations and 69 participants had normal genetic results. The ICT had a sensitivity of 63.06% for all alpha gene mutations and 100% for both heterozygous alpha⁰ and HbH disease, with a specificity of 91.30%. Examination of HbH preparation had a sensitivity of 34.23% overall, detecting 89% of heterozygous alpha⁰ and 100% of HbH disease with a specificity of 98.55%. Sample age did not affect overall results.

The ICT is a sensitive screening method for significant alpha mutations and detects the majority of homozygous alpha⁺ and nondeletional mutations. It demonstrates greater correlation with genetic testing than HbH preparation and could replace HbH preparation in the screening algorithm for alpha thalassaemia.