Screening of (-SEA) α-thalassaemia using an immunochromatographic strip assay for the ζ-globin chain in a population with a high prevalence and heterogeneity of haemoglobinopathies

Aims The presence of the zeta-globin chain is a good marker of (-(SEA)) alpha(0)-thalassaemia. We evaluated an immunochromatographic (IC) strip assay for zeta-globin in screening for (-(SEA)) alpha(0)-thalassaemia in a population with a high prevalence and heterogeneity of haemoglobinopathies. Methods The study was carried out on 300 screen positive blood samples of Thai individuals. The IC strip assay for the zeta-globin chain was performed on all samples. The results were interpreted with thalassaemia genotyping using standard haemoglobin and DNA analyses. Results Several thalassaemia genotypes were noted. Among the 300 subjects investigated, 79 had a positive IC strip assay for zeta-globin and (-(SEA)) alpha(0)-thalassaemia was identified in 40 of them. No (-(SEA)) alpha(0)-thalassaemia was detected in the remaining 39 samples with a positive IC strip test result or in the 221 samples with a negative IC strip test result. Further DNA analysis identified alpha(+)-thalassaemia in 25 of the 39 (-(SEA)) alpha(0)-thalassaemia negative samples. Using this IC strip assay in combination with a conventional screening protocol for (-(SEA)) alpha(0)-thalassaemia could provide sensitivity and specificity of 100% and 90.4%, respectively. Conclusions IC strip assay for zeta-globin is simple, rapid and does not require sophisticated equipment. Use of this test in addition to the existing screening protocol could detect potential (-(SEA)) alpha(0)-thalassaemia leading to a significant reduction in the workload of DNA analysis. This could be used in areas where haemoglobinopathies are prevalent and heterogeneous but molecular testing is not available.