Hemoglobin Electrophoresis & Sickle Cell Testing: Interpreting the Patterns
Hemoglobin Electrophoresis & Sickle Cell Testing: Interpreting the Patterns Trait vs. disease, thalassemia clues on the CBC, and why the newborn screen needs follow-up. Hemoglobin electrophoresis separates hemoglobin variants by their electrical charge, identifying the type and proportion of each hemoglobin present. It's the definitive test for diagnosing hemoglobinopathies—but it's also one of the most misunderstood results in primary care. Normal Hemoglobin Composition HbA (adult hemoglobin) : 95–98% (two alpha + two beta globin chains) HbA2 : 2–3.5% (two alpha + two delta chains) HbF (fetal hemoglobin) : <1% in adults (two alpha + two gamma chains; predominates in utero and declines after birth) The Key Patterns Condition HbA HbS HbA2 HbF CBC Clues Normal 95–98% 0 2–3.5% <1% Normal Sickle cell trait (AS) 55–60% 35–45% Normal Normal Usually normal CBC. No anemia. Benign in most contexts. Sickle cell disease (SS) 0 80–95% Normal 2–20% Chronic hemolytic anemia, reti...