Which lab pattern differentiates iron deficiency anemia from thalassemia trait?

• A. Iron deficiency shows high ferritin and low TIBC; thalassemia trait shows low iron stores with low RBC count
• B. Iron deficiency shows normal ferritin and low TIBC; thalassemia trait shows extremely high RBC count
• C. Iron deficiency shows low ferritin and high TIBC; thalassemia trait shows normal or increased iron stores with microcytosis and relatively normal or increased RBC count
• D. Iron deficiency shows high iron and low ferritin; thalassemia trait shows low iron and high TIBC

Answer: (C)

Assessing iron status markers helps distinguish iron deficiency anemia from thalassemia trait. Ferritin reflects stored iron, so in iron deficiency ferritin is low. The body responds by increasing transferrin capacity to bind iron, leading to a high TIBC. Serum iron is low and transferrin saturation is reduced, which fits iron deficiency.

In thalassemia trait there isn’t true iron depletion, so iron stores are normal or even increased, meaning ferritin is normal or high. Microcytosis is common, but RBC production is not impaired in the same way, so the RBC count is typically normal or increased rather than decreased.

Thus, the pattern described as low ferritin with high TIBC points to iron deficiency, while normal or increased iron stores with microcytosis and a relatively normal or increased RBC count points to thalassemia trait.