Hemoglobin electrophoresis is the most practical method of diagnosing hemoglobinopathies. Hemoglobins are genetically controlled and presence of abnormal hemoglobins is often associated with functional, physical and morphological abnormalities in the erythrocytes as well as pathological manifestations, such as hemolytic anaemia.
Normals show an HbA1 band and a faint HbA2 band.
Normal Values are HbA1 96-98.5%
This is a heterozygous state showing HbA1 and HbS with a normal amount of HbA2. The HbS concentration may vary from 20-50%.
This is a homozygous state showing almost exclusively HbS. A small amount of HbF (<15%) may also be present.
This state shows HbA1 and HbA2. The HbA2 band is elevated to twice normal levels with a concentration of 5-8% in approximately 60% of the cases. HbA2 values between 4-5% probably represent thalassaemia minor, but repeated red cell morphological abnormalities must be present for confirmation.
SICKLE C DISEASE
This is a heterozygous state showing HbS (45-55 %) and HbC (45-55 %).
This condition shows HbA1 (0-25 %), HbS (50-90 %), HbA2 (3-8 %) and HbF (2-20 %(.
THALASSAEMIA C DISEASE
This condition shows HbA1 (0-25%), HbF (2-20%) and HbC (60-90%). HbA2 cannot be measured.
This is a homozygous state showing almost exclusively HbC and up to 5 % HbF.
This condition shows HbF (70-90%), HbA1 (2-20%) and HbA2 (2-8%(.
CONDITIONS ASSOCIATED WITH ELEVATED FETAL HEMOGLOBIN (HbF) LEVELS
Postirradiation fibrosis of marrow
Malignancies involving marrow
Hereditary persistence of fetal hemoglobin
HbF syndrome with low HbA2 and carbonic anhydrase deficiency
Familial HbF elevation