RELIABILITY OF DIFFERENT RBC INDICES AND FORMULAS IN DISCRIMINATING BETWEEN ?-THALASSEMIA MINOR AND OTHER CAUSES OF MICROCYTIC HYPOCHROMIC ANEMIA

Abstract

Objective: Different indices and formulas of CBC parameters have been suggested as indicators of early stage screenings to detect couples with ?-thalassemia minor (BTM). In this study, we evaluated the accuracy of five previous published formulas and compared them to our new formula (?80-MCV?×?27-MCH?) in screening of ?-thalassemia.

Methods: All couples in the premarital ?-thalassemia screening program of Roodbar, Iran, for whom molecular analysis had been done were selected during two years. The red blood cell indices were applied to each formula, and a ROC curve was plotted for each one to check discriminative effectiveness in ?-thalassemia detection.

Result: None of the studied indices demonstrated 100% precision. However, we found that the Shine–Lal formula and our formula had the highest sensitivity in identifying BTM individuals. The highest specificity belonged to our formula and Sirdah formula.

Conclusion: Previous studies reported different sensitivities and specificities for the formulas. This can be attributed to different kinds of ?-gene mutations in various populations. As a result of this variation, RBC indices and mathematical formulas are variable in different populations. Undoubtedly, physicians in different areas should evaluate the accuracy of published formulas for their own populations in the discrimination of BTM from other causes of microcytic hypochromic anemia.