Validity assessment of nine discriminant functions used for the differentiation between iron deficiency anemia and thalassemia minor.

Iron deficiency anemia (IDA) and thalassemia minor are two of the most common causes of microcytic anemias worldwide. Because of similar red blood cell count parameters and blood picture, it was imperative to develop other measures that would differentially and correctly diagnose these two anemias. Several mathematical formulas and simple RBC indices have been introduced as simple, fast and inexpensive means of providing differential diagnosis for IDA and thalassemia minor. The Objective of this study was to apply and compare nine well-documented discriminant functions on a population of 153 confirmed cases of microcytic anemias (IDA n = 56, beta-thalassemia minor n = 47 and alpha-thalassemia n = 50) and to measure validity using Youden's Index. The results show that England and Fraser (E & F) Index had the highest Youden's Index value (98.2) in correctly differentiating between IDA and alpha- and beta-thalassemia minor, while Shine and Lal Index was found ineffective in differentiating between microcytic anemias in our population. E & F Index showed with great sensitivity and specificity to be the best discriminant function to differentiate between IDA and thalassemia minor cases.