Sensitivity, specificity and efficiency of different discriminative indexes in differentiation of thalassemia trait from iron deficiency anemia

A complete blood count (CBC), separation of haemoglobin molecules by electrophoresis at pH 8.4 followed by scanning densitometry and ethnic background, all together, are absolutely necessary in the diagnosis of beta-thalassemia trait. The aim of this study was to assess the specificity, sensitivity and efficiency of six different discriminative indexes in differentiation of thalassemia trait from iron deficiency anemia and if they alone may replace the haemoglobin electrophoresis. In this study there were analyzed 638 adult and child blood samples by haemoglobin electrophoresis at pH 8.4 on an agarose gel. For all these samples a CBC was initially performed on a fully automated system. 435 patients diagnosed with beta-thalassemia minor were further analyzed for thalassemia mutations. An individual evaluation for six discriminative indexes that included the CBC parameters was performed to differentiate thalassemia trait from iron deficiency anemia. The evaluation was performed on 542 samples with a clear diagnosis which included 107 samples with HbA2 within the reference range and 435 samples with the diagnosis of beta-thalassemia minor. The Shine and Lal index showed good specificity, sensitivity and efficiency. For 96 patients we could not evaluate these six discriminative indexes, the diagnosis being inconclusive. In conclusion CBC and the discriminative indexes cannot replace the haemoglobin electrophoresis in diagnosing beta thalassemia trait.