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.

Objective: The presence of the ζ-globin chain is a good marker of (--SEA) α0-thalassaemia. We evaluated an immunochromatographic (IC) strip assay for ζ-globin in screening for (--SEA) α0-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 ζ-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 ζ-globin and (--SEA) α0-thalassaemia was identified in 40 of them. No (--SEA) α0-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 α+-thalassaemia in 25 of the 39 (--SEA) α0-thalassaemia negative samples. Using this IC strip assay in combination with a conventional screening protocol for (--SEA) α0-thalassaemia could provide sensitivity and specificity of 100% and 90.4%, respectively.

Conclusions: IC strip assay for ζ-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) α0-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.