Question

A 29-year-old woman was found to have a hemoglobin of 7.8 g/dl, with a reticulocyte count of 0.8%. The peripheral blood smear showed microcytic, hypochromic anemia. Hemoglobin A2 and hemoglobin F levels were 2.4% and 1.3% respectively. The serum iron was low and the total iron binding capacity (TIBC) was raised at 420 mcg/dL. The most likely cause of anemia is:

• A. Iron deficiency anemia
• B. Beta-thalassemia minor
• C. Sideroblastic anemia
• D. Anemia due to chronic infection

Hint:

Low serum iron with a raised TIBC and a normal hemoglobin A2 points to iron deficiency, not thalassemia trait.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
A young woman has a low hemoglobin of 7.8 g/dl with a low reticulocyte count of 0.8 percent, meaning the bone marrow is not responding briskly to the anemia. The blood film shows small, pale (microcytic, hypochromic) red cells. Hemoglobin A2 is 2.4 percent and hemoglobin F is 1.3 percent, both within or below the normal range, and the serum iron is low while the total iron binding capacity (TIBC) is raised at 420 mcg/dL. We need to find the most likely cause of this anemia.

Step 2: Key Concept:
Microcytic hypochromic anemia has a short differential: iron deficiency anemia, thalassemia trait, sideroblastic anemia, and anemia of chronic disease. Iron studies and the hemoglobin electrophoresis pattern are what separate these from each other. In iron deficiency, serum iron is low and TIBC (which reflects unbound transferrin) rises because the body is hungry for iron. In beta-thalassemia minor, iron stores and TIBC are usually normal or even high, and hemoglobin A2 is typically raised above 3.5 percent because less normal beta chain is made.

Step 3: Detailed Explanation:
Here the serum iron is low and the TIBC is raised at 420 mcg/dL, a combination that is the hallmark of true iron deficiency rather than thalassemia trait. Hemoglobin A2 at 2.4 percent is within the normal to low range, not the raised level (above 3.5 percent) expected in beta-thalassemia minor, so thalassemia trait is unlikely. Sideroblastic anemia usually shows a high or normal serum iron with a low TIBC, the opposite of what is seen here, so it does not fit. Anemia of chronic disease usually shows a low serum iron with a low or normal TIBC, again the opposite of a raised TIBC, so that also does not fit. The pattern of low serum iron with a high TIBC is specific for iron deficiency anemia.

Step 4: Final Answer:
The most likely cause of this anemia is iron deficiency anemia, option (1).