Validity of naked eye single tube red cell osmotic fragility test (NESTROFT) in screening of beta-thalassemia trait

Thalassemia is the most common single gene disorder which is not completely cured. It is needed to find a reliable and cost-effective prevention method for screening the disease. For the next step, it is needed to give proper education, genetic consulting and prenatal diagnosis for the patients and finally selective termination of affected fetuses. The aim of this study was to evaluate effectiveness of the Naked Eye Single Tube Red Cell Osmotic Fragility Test (NESTROFT) as a screening test for beta-thalassemia trait. In this descriptive –analytical study, NESTROFT was applied to a total of 158 subjects who were divided into three groups. Group I was comprised of 51 individuals belonging to parents whom at least one of the children was suffering from ß-thalassemia major, group II was consisted of 51 normal individuals and finally group III was comprised of 56 individuals with iron deficiency. The findings of this study showed that sensitivity of the test was as high as 100 percent and specificity was 86.9 percent. The predictive value of the positive test was 78.5 percent and the negative test was as high as 100 percent. False positive results were obtained in 14 cases with iron deficiency. NESTROFT emerged as a highly sensitive, inexpensive and easy to perform test for exclusion of beta-thalassemia trait. It is therefore a suitable test for large-scale use in a developing country such as Iran, which has got limited financial and technical resources.