Laboratory findings in iron deficiency versus thalassemia minor

Transfusion-dependent thalassemia is usually obvious, but distinction between iron deficiency and thalassemia minor is a common problem. Other than iron studies, the RBC count and reticulocyte count are often the most useful for making the distinction. In iron deficiency, the RBC count and reticulocyte count are typically low; in thalassemia, the RBC count is typically high and the reticulocyte count is normal to slightly increased. All individuals being evaluated for thalassemia should have iron studies to document that iron stores are adequate. If iron deficiency is present, it should be corrected prior to thalassemia evaluation because iron deficiency can alter hemoglobin patterns.