Evaluation of Red Cell Indices and Discriminant Functions in the Detection of Beta Thalassemia Trait

ABSTRACT

Background: The heterozygous state of Beta-Thalassemia i.e. Beta-Thalassemia Trait (BTT) is usually not associated with any clinical symptoms and possesses abnormality in only a single BetaGlobin gene. Materials and methods: The present study was undertaken from October 2015 to October 2017 in the Department of Pathology of Mahatma Gandhi Medical College and Hospital. In our study, a total of 100 subjects were included with mild or no anemia (Hemoglobin >8 gm/dl) who were referred to the central lab for hemoglobin screening. Hb A2 values were determined by Capillary Hemoglobin electrophoresis for all 48 (BTT) and 52 (Normal/non BTT) subjects. The complete hemogram was done by automated hematology analyzer. The values of red cell indices TRBC, MCV and MCH and six discriminative indices were evaluated for detection of β-thalassemia trait. The results were compiled in tabular form and bar diagram. Results: In the present study, the patients in the BTT group had statistically significantly decreased mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) and increased TRBC count as compared to those in non BTT group. Among the six discrimination indices used highest sensitivity was found for Shine and Lal index (87.5%) followed by Mentzer index (79.16%). The highest specificity was found for E and F (88.46%) followed by RDWI (84.61%). Youden’s index was highest for Mentzer index (61.85%) followed by RDWI (55.44%). Conclusion: From this study, we thus conclude that although no screening test can diagnose β− Thalassemia Trait with 100% sensitivity or specificity, among the hematological parameters MCV, TRBC and MCH most efficiently discriminates β−Thalassemia Trait from other microcytic, hypochromic anemia. Mentzer index with CBC may be the simple, low cost, rapid and can be reliably Prachi Gupta, BP Nag, Abha Mathur. Evaluation of Red Cell Indices and Discriminant Functions in the Detection of Beta Thalassemia Trait. IAIM, 2019; 6(3) 50-59. Page 51 used as a screening test for thalassemia as a routine. However none of the formulas are 100% sensitive and specific.