Which of the following is the best test to differentiate beta-thalassemia minor from iron deficiency anemia?

Which of the following is the best test to differentiate beta-thalassemia minor from iron deficiency anemia?

• A. Hemoglobin A2 quantitation
• B. Hemoglobin electrophoresis (cellulose acetate, alkaline pH)
• C. Solubility test
• D. Complete blood count

Answer: (A)

Distinguishing beta-thalassemia minor from iron deficiency anemia hinges on the level of Hemoglobin A2, because beta-thalassemia trait typically produces a distinct rise in HbA2 while iron deficiency does not. Quantifying HbA2 precisely (often by HPLC) gives a reliable discriminator: HbA2 is usually elevated above about 3.5% in beta-thalassemia trait, whereas in iron deficiency the HbA2 fraction remains normal or is reduced. Hemoglobin electrophoresis can show the presence of abnormal Hb fractions and support suspicion of beta-thalassemia, but without precise quantitation it can be less definitive and affected by technical factors. A solubility test targets hemoglobins relevant to sickle cell disease and isn’t helpful for distinguishing these two conditions. A complete blood count will reveal microcytosis in both conditions and by itself cannot differentiate them.

Distinguishing beta-thalassemia minor from iron deficiency anemia hinges on the level of Hemoglobin A2, because beta-thalassemia trait typically produces a distinct rise in HbA2 while iron deficiency does not. Quantifying HbA2 precisely (often by HPLC) gives a reliable discriminator: HbA2 is usually elevated above about 3.5% in beta-thalassemia trait, whereas in iron deficiency the HbA2 fraction remains normal or is reduced.

Hemoglobin electrophoresis can show the presence of abnormal Hb fractions and support suspicion of beta-thalassemia, but without precise quantitation it can be less definitive and affected by technical factors. A solubility test targets hemoglobins relevant to sickle cell disease and isn’t helpful for distinguishing these two conditions. A complete blood count will reveal microcytosis in both conditions and by itself cannot differentiate them.