American Board of Internal Medicine (ABIM) Certification Practice Exam

Which condition is associated with normal hemoglobin electrophoresis results?

1. Iron deficiency anemia

2. β-thalassemia major

3. α-thalassemia trait

4. Sickle cell disease

The correct answer is: α-thalassemia trait

Normal hemoglobin electrophoresis results indicate that the hemoglobin types present in the patient’s blood are within the expected ranges for a healthy individual. In the case of α-thalassemia trait, individuals typically exhibit a normal hemoglobin electrophoresis profile because the condition primarily involves a reduced production of α-globin chains yet does not affect the overall balance of hemoglobin molecules enough to alter the electrophoretic patterns significantly. Individuals with α-thalassemia trait may have some mild changes in red blood cell indices or minor variations in hemoglobin concentrations, but these do not typically show an abnormal pattern on electrophoresis when compared to normal controls. In contrast, conditions like iron deficiency anemia, β-thalassemia major, and sickle cell disease all demonstrate distinct abnormalities in hemoglobin types when analyzed through electrophoresis. For example, patients with sickle cell disease have elevated amounts of hemoglobin S, which would produce a clear and identifiable abnormality on an electrophoresis test. Similarly, β-thalassemia major usually shows an abnormal distribution of hemoglobin due to increased levels of fetal hemoglobin and absent beta chains, which would be detectable on electrophoresis. Iron deficiency anemia might also show changes due to the effects