VALIDITY OF NESTROFT IN SCREENING AND DIAGNOSIS OF BETA-THALASSEMIA TRAIT

Validity of naked eye single tube red cell osmotic fragility test ('Ne stroft') was evaluated on 253 individuals divided into two groups, The HbA(2) values estimated:in each child was taken as gold standard, Gro up I comprised of 93 individuals belonging to families in which at lea st one of the children was suffering from beta-thalassemia major and g roup II consisted of 160 normal children. The sensitivity of 'Nestroft ' was 95.59 per cent (grp I) & 85.71 per cent (grp II), specificity wa s 84.2 per cent (grp I) and 81.7 per cent (grp II) with a negative pre dictive value as high as 99.21 per cent in general population, The res ults of the test were assessed by two independent observers and P valu es of 0.75 and 0.69 were found in grp I and grp II, respectively, The values clearly showed that the interobserver variation was statistical ly insignificant thus proving it to be an objective test. Comparative analysis of 'nestroft' with red cell indices, i.e. MCV (<70 fl) and RB C count (> 4.5 x 10(12)/l) revealed it to be the most sensitive and sp ecific test. 'Nestroft' has emerged as the single most effective, inex pensive and easily reproducible test of population screening for beta- thalassemia trait.