Mediterranean Journal of Hematology and Infectious Diseases (Aug 2014)
SCREENING PARADIGM FOR ?-THALASSEMIA CARRIERS; FROM CLINICAL TO MOLECULAR
Abstract
? thalassemia (?-thal) represents a major health problem worldwide and particularly in Egypt. Its prevention, when compared to treatment, is found to be cost-effective, possible and practical. This work aimed to evaluate the effectiveness of diagnostic techniques in detection of the ?-thalassemia carrier state. The present work included 1627 child and adolescent of both sexes presenting as outpatients to clinics of Ain-Shams University Hospitals during period from 1/11/2009 to 30/6/2010. In the first phase microcytic hypochromic for age CBCs were selected. In the second phase, Iron profile and HPLC testing were performed. Molecular characterization by PCR reverse hybridization for detection of 22 common ?-globin gene mutations was done as a final step. The 280 Microcytic hypochromic cases selected were further analyzed by iron profile & HPLC. This revealed 100 suspected cases in whom a Hb A2 >4% was able to identify ? thalassemia carriers with 97.4% sensitivity, 72.7% specificity and 92% diagnostic accuracy while a HbA2 borderline value from 3.6% to 4% provided 100% sensitivity & 70% diagnostic accuracy. Further genotyping of the latter group confirmed presence of Beta thalassemia related mutations in 74% of the suspected cases. Conclusion: In addition to HPLC, as a reliable primary screening tool for ?-thalassemia trait (?TT), molecular testing is mandatory for selected cases with borderline Hb A2 values.