Which electrophoresis finding is typical of beta-thalassemia trait?

Which electrophoresis finding is typical of beta-thalassemia trait?

• A. Increased HbA2
• B. Increased HbS
• C. Decreased HbA
• D. Increased HbF

Answer: (A)

In beta-thalassemia trait, the production of the beta-globin chains is reduced. Because HbA (which is alpha2 beta2) relies on beta chains, its amount drops. To compensate, the body increases production of other hemoglobins that use delta chains, leading to a higher proportion of HbA2 on electrophoresis. HbF can be mildly elevated as well, but the standout finding is the rise in HbA2. That’s why increased HbA2 is the best answer. The other possibilities don’t fit as well: a large increase in HbS would point to sickle cell conditions; a simple decrease in HbA is a consequence of reduced beta chains but not as characteristic as the specific rise in HbA2; and HbF can be elevated but is less diagnostic for beta-thalassemia trait than the increased HbA2.

In beta-thalassemia trait, the production of the beta-globin chains is reduced. Because HbA (which is alpha2 beta2) relies on beta chains, its amount drops. To compensate, the body increases production of other hemoglobins that use delta chains, leading to a higher proportion of HbA2 on electrophoresis. HbF can be mildly elevated as well, but the standout finding is the rise in HbA2. That’s why increased HbA2 is the best answer.

The other possibilities don’t fit as well: a large increase in HbS would point to sickle cell conditions; a simple decrease in HbA is a consequence of reduced beta chains but not as characteristic as the specific rise in HbA2; and HbF can be elevated but is less diagnostic for beta-thalassemia trait than the increased HbA2.