84Hemoglobinopathies are among the most common genetic diseases in the world. Approximately 700 structural variants of the hemoglobin molecule have been described. Many of these have been discovered incidentally and are not of clinical significance; About 200 variants hemoglobin variants are clinically significant and may cause microcytosis, anemia, jaundice, erythrocytosis or cyanosis.
The clinical indications for ordering hemoglobin electrophoresis include:
Unexplained hemolytic anemia
Positive sickle cell or solubility test
Microcytic anemia not explained by iron deficiency, lead toxicity, or chronic disease
A blood smear with abnormal erythrocyte morphology such as sickle cells or target cells
Positive neonatal screen
Positive family history of a hemoglobinopathy
Either a qualitative (structural) or quantitative abnormality of one or more of the globin chains causes a hemoglobinopathy. Structural variants of hemoglobin can be identified by electrophoresis. A clinical pathologist interprets the results. Interpretation of hemoglobin electrophoresis patterns requires knowledge of the patient's age, transfusion history, CBC and peripheral blood smear results.
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Adult reference range is 96 - 99% Hb A, < 3.5% Hb A2 and < 2% Hb F.
Specimen requirement is one lavender top (EDTA) tube of blood for adults or 2 lavender top microtainer tubes for children.
