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Separating Thalassemia Trait and Iron Deficiency by Simple InspectionThe Author’s ReplyThe Author’s Reply

Claude Owen Burdick, George Ntaios MD, Dinesh Rathod MD
DOI: http://dx.doi.org/10.1309/AJCPC09VRAXEASMH 444-445 First published online: 1 March 2009

To the Editor

Recently the Journal has published interesting articles and correspondence on the subject of the separation of thalassemia trait (TT) from iron deficiency anemia (IDA) by the use of RBC indices. Rathod et al1 calculated 6 previously described indexes on 200 patients and correlated the findings with the findings of hemoglobin electrophoresis and iron studies. They favored the Shine and Lal index.2 Harrington et al3 used morphologic findings for the same purpose and, in the process, generated data showing red cell distribution width (RDW) to be a good discriminatory tool. Ntaios and Chatzinikolaou4 criticized the use of RDW as a discriminator, having previously found it of little value.

I believe it is usually easiest to separate TT and IDA by simple inspection, rather than using a mathematical index, using the following rules: (1) TT rarely causes anemia of less than 10 g/dL (100 g/L) of hemoglobin. (The hemoglobin value is usually more than 11 g/dL [110 g/L].) (2) The RBC count in TT is more than 5.0 x 106/μL (5.0 x 1012/L) and in IDA is less than 5.0 x 106/μL (5.0 x 1012/L). (3) The RDW in IDA is more than 17% and in TT is less than 17%.

Discordances usually indicate a combined anemia. Here are a few illustrative true patient examples. (1) A …

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