Review Question - QID 210986

This patient with an asymptomatic microcytic anemia, decreased levels of hemoglobin A1, and increased hemoglobin A2 most likely has beta-thalassemia minor, which would demonstrate codocytes on blood smear.

Beta-thalassemia is a form of anemia that is caused by a decrease in the production of beta-hemoglobin chains. Defective production from a single gene will result in beta-thalassemia minor, which is often asymptomatic due to effective compensation by the normal gene. Therefore, patients will not notice that they have this disease until it is discovered incidentally on blood workup. Notably, since there is decreased production of the normal beta-hemoglobin chain, the body may compensate by overproducing other chains such as delta-hemoglobin resulting in hemoglobin A2 and gamma-hemoglobin resulting in hemoglobin F. These variant forms of hemoglobin can be discovered on hemoglobin electrophoresis.

Incorrect Answers:
Answer 1: All cells would appear normal if this patient had anemia from acute blood loss; however, hemorrhage would not present with increased concentrations of hemoglobin A2.

Answer 3: Megaloblasts would be seen if this patient had anemia from vitamin B12 or folate deficiency; however, these deficiencies would present with a macrocytic megaloblastic anemia.

Answer 4: Sideroblasts would be seen if this patient had anemia from lead poisoning; however, lead poisoning would not present with increased concentrations of hemoglobin A2.

Answer 5: Schistocytes would be seen if this patient had anemia from a microangiopathic cause; however, these causes would present with a normocytic anemia as well as a normal level of hemoglobin A2.

Bullet Summary:
Beta-thalassemia minor is asymptomatic but will present with increased hemoglobin A2 and hemoglobin F concentrations in the blood.