, some of which is glycated (2), accounts for the majority (70%-95%) of Hb species in newborns.
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.
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.
In the healthy newborn, Hb F
(a2[gamma]2) is the major hemoglobin (~75%).
Additionally, patients with increased Hb F
(>10%) will have a falsely low Hb [A.
var] or high Hb F
concentrations can be recognized by the separate elution of variant peaks or by abnormally high peaks on HPLC, and these abnormal findings arise mostly from genetic alterations in the globin genes (2,3).
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.
2] and Hb F
and identification of Hb variants (11,12).
The percent concentrations in the current study are lower than the published cord blood data by 15% for all Hb F
and by a median 36% for the Hb in other hetero- and homozygous patterns (range, 22-40%).
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