When is ordering hemoglobin (Hb) electrophoresis recommended?

When to Order Hemoglobin Electrophoresis

Order hemoglobin electrophoresis when you identify microcytic hypochromic anemia with normal iron studies (ferritin, transferrin saturation, and iron levels all normal), particularly in patients from ethnic backgrounds at risk for hemoglobinopathies. 1

Primary Clinical Indications

Microcytic Anemia with Normal Iron Studies

• Order hemoglobin electrophoresis specifically when MCV is reduced but ferritin, transferrin saturation, and iron levels are all normal 1
• This prevents unnecessary gastrointestinal investigations in patients who actually have thalassemia trait or other hemoglobinopathies 1
• Pay particular attention when the MCV is disproportionately low relative to the degree of anemia—this pattern strongly suggests thalassemia trait 1

Suspected Sickle Cell Disease

• Order when clinical presentation includes: normocytic normochromic anemia with hemolysis markers, painful crises, or family history of sickle cell disease 1
• Consider in patients presenting with acute chest syndrome, recurrent vasoocclusive pain, dactylitis, or unexplained hemolytic anemia 2

Suspected Hemoglobinopathy Variants

• Order when evaluating unexplained cyanosis or methemoglobinemia, especially with family history 3
• Consider in patients with hemolytic anemia that doesn't fit typical patterns 2

Technical Considerations

Preferred Testing Methods

• HPLC (high-performance liquid chromatography) or capillary electrophoresis should be the primary method, with HPLC being the gold standard for both screening and quantification 1
• Alkaline pH electrophoresis (pH 8.6) serves as initial screening but requires confirmatory testing 1
• Electrophoresis alone is insufficient because some variants are electroforetically silent and will be missed 1, 3

Confirmatory Testing Requirements

• Some hemoglobin variants co-migrate at certain pH levels (e.g., Hb O(Arab) co-migrates with Hb C at alkaline pH and near Hb S at acidic pH), requiring electrophoresis at both alkaline and acidic pH for accurate diagnosis 2
• For suspected hemoglobin M variants, directed sequencing of α and β globin genes is technically simpler, more widely available, and more specific than electrophoresis alone 3

Critical Pitfalls to Avoid

Timing Issues

• Do not order hemoglobin electrophoresis in neonates or recently transfused patients if using solubility testing, as false negatives occur 1
• In transfused patients with sickle cell disease, complete absence of HbA on electrophoresis during hemolysis indicates selective destruction of transfused cells (severe DHTR rather than hyperhemolysis syndrome) 4

Interpretation Errors

• Never skip family studies when hemoglobinopathy is identified—this is essential for genetic counseling and family planning 1, 3
• Do not interpret HbA1c in patients with hemoglobinopathies unless using assays without interference 1
• Do not order hemoglobin electrophoresis for routine anemia workup without first evaluating iron studies and red cell indices 1

Communication

• Always clearly communicate the suspected diagnosis on laboratory request forms to ensure appropriate processing and interpretation 1

Special Populations

Pregnancy

• Women with known sickle cell disease should be managed in specialized obstetric units given 1-3% maternal mortality and 1-8% perinatal mortality rates 1
• These patients have high complication rates: 57% painful crises, 38% cesarean delivery, 23% ICU admission 1
• Universal hemoglobin electrophoresis in pregnancy has higher sensitivity (100%) compared to selective screening based on RBC indices and solubility testing (88.9% sensitivity), though the latter approach costs approximately $18 less per patient 5