In laboratorytesting to confirm a diagnosis of a b
-thalassemia trait diagnosis, HbA2
levels should be considered in conjunction with family historyand additional laboratory data, including serum iron and iron binding capacity, red cell morphology, hemoglobin, hematocrit, and mean corpuscular volume (MCV).
Patients with a combination of iron deficiency and b
-thalassemia may have a normal A2
level. In these cases, elevated A2
level cannot be used to screen for b
-thalassemia in these cases.
|Patient State||Hb A2 Level||Hb F Level|
|Homozygous b-thalassemia||Normal or Increased||80-100%|
|Heterozygous HPFH||Less than 1.5%||10-20%|