Validity of Naked Eye Single Tube Red Cell Osmotic Fragility Test in Screening of ß-Thalassemia Trait

Abstract

Background: Worldwide the hemoglobin disorders are the most common clinically serious single gene disorders and are often regarded as incurable and expensive to treat. Objective: To find out sensitivity, specificity and predictive values of Naked Eye Single Tube Red Cell Osmotic Fragility Test (NESTROFT) for detection of carriers of ß-Thalassemia. Methods: This descriptive analytic type of study was carried out in the Department of Pediatrics of Sylhet MAG Osmani Medical College Hospital, Sylhet, from July 2006 to June 2008. A total of 70 samples, 35 cases and 35 suitably matched controls were enrolled. In this study, siblings, parents and first degree cousins of patients of β-thalassemia major who had Hemoglobin A2>3.6%+HbA on hemoglobin electrophoresis were selected randomly as cases and the same of whom had Hemoglobin A2 (2.5±0.2)+ HbA on hemoglobin electrophoresis were selected as controls. Naked Eye Single Tube Red Cell Osmotic Fragility Test (NESTROFT) was done from the cases and controls. Results: Sensitivity and specificity of NESTROFT in the diagnosis of carriers of β-thalassemia were found 94.3 % and 88.6 % respectively. The positive predictive value and negative predictive value of NESTROFT in the diagnosis of carriers of βthalassemia were found 89.1% and 94% respectively. Conclusion: NESTROFT is a valid screening test for detection of ß-thalassemia trait andNESTROFT may be used as an alternative to hemoglobin electrophoresis to detect ß-thalassemia trait in Bangladesh.