New mathematical formula for differentiating thalassemia trait and iron deficiency anemia in thalassemia prevalent area: a study in healthy school-age children.

Iron deficiency anemia(IDA) and thalassemiasare common diseases especially in the Mediterranean, Middle East and Asian regions. Both conditions show the same clinical findings of hypochromic and microcyticred blood cells. Although previous studies have devised mathematical formulae to differentiate between these two conditions, the prevalence of a- and b- thalassemiasamong the affected populations may undermine the accuracy of these formulae. This study generated a new formula that was able to differentiate IDA and thalas- semia traits and to determine the incidence rates of IDA and thalassemiatraits. A total of 345 healthy Thai children with a mean age (± SD) of 11.3 (± 1.7) years were enrolled. Complete blood count, iron status, hemoglobin typing and DNA for a-1 thalassemiaidentification were investigated. Discriminant analysis was used to create a new mathematical formula containing significant variables to dif - ferentiate between IDA and thalassemiatraits. The new formula of (1.5 Hb-0.05 MCV >14) had a receiver operator characteristic curve of 0.92 in differentiating thalassemiatraits from IDA, with sensitivity and specificity of 84.6 and 87.5%, respectively. The incidence of IDA and thalassemiatraits in the study group was 12% and 32%, respectively. This formula should be useful as a screening tool to differentiate between these two conditions.