Clinical Indications for Hemoglobin Electrophoresis

Unexplained Hemolytic Anemia
Positive Sickling Test or Solubility Test
Microcytic Anemia not due to Iron Deficiency, Lead or Chronic Disease
Indicative Results on Blood Smear: Sickled Cells, Target Cells
Positive Neonatal Screen
Positive Family History of Hemoglobinopathy
Screening: Sickling Test and Solubility Test

Positive in Heterozygous Sickle Cell Diseases and Sickle Cell Anemia
Negative in HbC Disease and HbC Trait (except C-Harlem)
False negatives if HbS < 20%, ie in very young infants or severe anemia

Interpretation of hemoglobin electrophoresis requires knowledge of previous transfusions, age of patient, CBC and peripheral blood smear results.



Age-Related Reference Ranges for Hemoglobin F (May vary with lab)

Age % HbF
Newborn 50-85
1 Month 50-75
2 Months 25-60
3 Months 10-35
6 Months 8
1 Year < 2
Adult < 2
Adult Homozygote Hereditary Persistence of Fetal Hb(HPFH): 100% HbF
Adult Heterozygote HPFH: 20-40% HbF
In the Absence of Previous Transfusions:
1. Hemoglobin A1 Present with Hemoglobin S:
HbA1 > HbS: Sickle Cell Trait
HbS > HbA1: Double Heterozygote HbS and beta+-thal
HbS < 35%: Consider Double Heterozygote HbS and alpha-thalassemia, MCV low
2. Hemoglobin A1 Absent:
HbS > 80%: Sickle Cell Disease
HbC > 90%: Hemoglobin C Disease
HbS/HbC in equal amounts: SC Disease
HbA2 > 5%: Consider Double Heterozygote HbS and betao-thal
HbF >20% (adults): Consider Double Heterozygote HbS and HPFH

Heterozygous Hemoglobin S


1. AS Sickle Cell Trait: HbS and normal HbA1
HbA1: always dominates, typically 50-65%
HbS: typically 35-45%
HbA2: within normal range or slightly increased, 1.5-4%
HbF: frequently higher for age in infants
2. S beta+-thal Double Heterozygote: HbS and beta plus-thalassemia
HbS: always dominates, typically 60-80%
HbA1: 15-30%
HbA2: elevated to 3-8%
HbF: 2-20%, higher for age in infants
3. S betao-thal Double Heterozygote: HbS and beta null thalassemia
HbS: 75-90%
HbA1: absent unless transfused
HbA2: 5-8%
HbF: 5-20% in adults, higher for age in infants
4. S alpha-thal Double Heterozygote: HbS and alpha-thalassemia
The % HbA1 greatly exceeds the % Hb S beyond the typical 60:40 ratio; consider this if
there is less then 35% HbS and the MCV is low
5. HbSC Double Heterozygote: HbS and HbC (SC Disease)
HbA1: absent unless previously transfused
HbS: 45-55%
HbC: 45-55%
HbF: up to 7% in adults; higher for age in infants
6. Double Heterozygote: HbS and Hereditary Persistence Fetal Hb (HPFH)
HbA1: absent unless previously transfused
HbS: 60-80%
HbF: 20-40%
HbA2: 1.5-4%
Sickle Cell Anemia: Homozygous HbS
HbA1: absent unless patient has been transfused
HbS: over 80%
HbF: up to 10% in adults; higher for age in infants
HbA2: 2-4%

Hemoglobin C Disease: Negative in Sickling Test & Solubility Test
HbA1: absent unless previously transfused
HbC: over 90%
HbF: up to 7% in adults; higher for age in infants