NESTROFT as a screening test for the detection of thalassaemia and common haemoglobinopathies - An evaluation against a high performance liquid chromatographic method

The NESTROFT method (Naked Eye Single Tube Red Cell Osmotic Fragility Test) was evaluated against a high performance liquid chromatographic (HPLC) method for its usefulness in screening for β-thalassaemia and some of the common haemoglobinopathies. Blood samples (137) from patients with suspected haemoglobin disorders were analyzed by both methods. Among the 63 patients with heterozygous β-thalassaemia on HPLC, NESTROFT was positive for 49,'doubtful' for 13 and negative for 1. Of the 32 patients with other haemoglobin disorders, 28 were positive on NESTROFT and 4 were 'doubtful'. Of the 42 'normal' samples, NESTROFT was positive for 6, 'doubtful' for 8 and negative for 28. This test showed an overall sensitivity of 98.7 per cent, specificity of 66.6 per cent, positive predictive value of 87 per cent and negative predictive value of 96.5 per cent. We conclude that, NESTROFT is a suitable test for screening for β-thalassaemia and the common haemoglobinopathies seen in India. It is easy to perform, simple, inexpensive and does not require sophisticated equipment. Subjects who are NESTROFT 'positive' or 'doubtful' deserve further investigation.