The Diagnostic Performance of Red Cell Distribution Width and Mentzer Index for Discrimination between Iron Deficiency Anemia and Beta Thalassemia Trait

Abstract
Background: Mild microcytic hypochromic anemias due to Iron Deficiency (IDA) and Beta Thalassemia Trait (b-TT) continue to be a cause of significant burden to the society, particularly in the poorer developing countries, as b-TT is often misdiagnosed as iron deficiency anemia in children because the two produce similar hematologic abnormalities on Complete Blood Count (CBC), and IDA is much more prevalent. So it is important to differentiate between thalassem-ic and non thalassemic microcytosis as both conditions share many characteristics and have important clinical implications. Thus a correct diagnosis in patients with microcytic anemia can provide an indication for supplementing iron to IDA patients, for avoiding unnecessary iron therapy in thalassemia carriers and of course also for preventing severe and lethal forms of thalassemia syndromes in the framework of premarital counseling in high-prevalence areas.
Aim of Study: To evaluate the diagnostic performance of simple and costless methods, i.e. red cell distribution width (RDW%), red cell distribution width index (RDWI) and Mentzer index for discrimination between IDA and b-TT.
Patients and Methods: The study was conducted on 50 patients with microcytic hypochromic anemia, 26 males and 24 females aged from 2- 4 years recruited from the Hematology Outpatient Clinic. In addition, 15 apparently healthy children with matchable age and sex, selected from relatives of the patients were enrolled in the study as a control group.
Results: The highest sensitivity rate (100%) was shown by RDW index but with a low specificity rate, (79.3 1%) followed by Mentzer as well as Green and King indices with a sensitivity=95.24% for each, while the specificity rate of Mentzer index was 93. 1% and that of Green and King index was 79.31%.
Conclusion: Among the studied indices, reduced Mentzer index <13 showed the highest diagnostic performance for discrimination between iron deficiency anemia and beta thalassemia trait by detection of increased Hb A2 >3.5% as proved by ROC test.
Recommendation: As discrimination between iron defi-ciency anemia and beta thalassemia trait is very essential to reach the suitable therapeutic strategy for such cases, therefore, we recommend the use of Mentzer index as a feasible, costless method with a high diagnostic performance for preliminary discrimination between those two diseases.