HEMOGLOBIN A(2) LEVELS IN HEALTHY-PERSONS, SICKLE-CELL DISEASE, SICKLE-CELL TRAIT, AND BETA-THALASSEMIA BY CAPILLARY ISOELECTRIC-FOCUSING

Simultaneously measuring major and minor hemoglobin (Hb) variants by c apillary isoelective focusing, we obtained HbA(2) intervals in healthy volunteers (n = 412) (reference value) and patients with HbS or beta- thalassemia. We classified normal HbA(2) reference intervals into thre e age groups: 5 months or younger (1.2% +/- 1.5%), 6 months to 1 year (2.2% +/- 0.9%), and 1 year or older (2.4% +/- 0.9%). These intervals were comparable to those used with other methods. Patients 1 year of a ge or older with HbS had significantly higher HbA, levels (sickle cell trait 2.9% +/- 0.9%; sickle cell anemia, 2.8% +/- 1.0%; P<.05). Altho ugh reference HbA, intervals overlapped those in patients with HbS, no overlap in HbA(2) levels was noted between these groups and patients with beta-thalassemia (observed range, 4.3% to 7.5%). The higher than normal HbA(2) interval in patients with HbS must be considered before a diagnosis of sickle cell trait or sickle cell disease with beta-thal assemia is made.