Hemoglobin variants and increases in circulating fetal hemoglobin (Hb F),  (defined as an Hb F level >2%) have been reported to interfere with some assay methods for [Hb A.
The Hb F level was estimated from the G7 or G8 Hb F percentage.
At the time it was assumed that the Hb F of 15% was attributable to a combination of the patient's age and recovery from an oxidative haemolytic crisis.
In each of the seven cases the Hb F level is somewhat less than that usually associated with Hb E/[[beta].
Additionally, patients with increased Hb F (>10%) will have a falsely low Hb [A.
1c] antibody or if a patient has a greatly increased Hb F percentage, Hb [A.
Alkaline electrophoresis is rapid, reproducible, and capable of separating common hemoglobin variants, such as hemoglobin A (Hb A), Hb F, Hb S, and Hb C, but Hb S, Hb D, Hb G, and Hb Lepore are unresolved from each other, as are Hb C, Hb [A.
Hemoglobin fraction analysis by cation-exchange HPLC has the advantage of quantifying Hb F and Hb [A.
2] (3,4), and alkaline denaturation, radial immunodiffusion, and automated HPLC for Hb F
2], Hb E, and Hb F
, and detection of erythrocytes containing Hb H inclusion bodies, provide an accurate diagnosis (1-4).
Cation-exchange HPLC with a SynChropak CM300 column and a sodium acetate gradient resolves Hb El, completely behind the Hb F
2] and Hb F
and screening for the presence of Hb variants were accomplished by cation-exchange HPLC with the [beta]-thalassemia Short Program in the Variant (Bio-Rad Labs.