Given hemoglobin (Hb) electrophoresis results showing Hb A approximately 69%, Hb A2 approximately 3.6%, Hb C approximately 27%, and normal Hb F, what are the next steps in management?

Hemoglobin AC Trait: Confirm Diagnosis and Assess for Coexisting Conditions

These results indicate hemoglobin AC trait (heterozygous hemoglobin C), which requires confirmation with repeat testing and evaluation for concurrent iron deficiency or thalassemia that may be contributing to any anemia present.

Interpretation of Results

Your hemoglobin electrophoresis shows:

• HbA 69.4% and HbC 27.0%: This pattern is diagnostic of hemoglobin AC trait (heterozygous HbC carrier state)
• HbA2 3.6%: This is at the upper limit of normal (normal range 2.5-3.5%), which may suggest concurrent beta-thalassemia trait
• HbF normal: Rules out hereditary persistence of fetal hemoglobin

This is a clinically benign condition in isolation, but the slightly elevated HbA2 warrants further evaluation 1.

Immediate Next Steps

1. Complete Blood Count with Indices

Obtain CBC to assess:

• Hemoglobin level: Determine if anemia is present
• MCV and MCH: Microcytosis (MCV <80 fL) and hypochromia suggest either iron deficiency, thalassemia trait, or both
• Red cell morphology: Target cells and crystal-like erythrocytes are characteristic of HbC trait 2

2. Iron Studies

Essential to distinguish iron deficiency from thalassemia trait 1:

• Serum ferritin <30 μg/L indicates iron deficiency
• Transferrin saturation <15% supports iron deficiency
• If ferritin is low, this explains microcytosis and may be masking thalassemia

Critical caveat: The specificity of MCV for iron deficiency is limited because microcytosis occurs in both iron deficiency and thalassemia. In thalassemia, MCV is typically reduced out of proportion to the degree of anemia 1.

3. Alpha-Thalassemia Gene Testing

Given the borderline elevated HbA2 (3.6%), test for alpha-thalassemia deletions:

• Alpha-thalassemia trait can normalize HbA2 levels even when beta-thalassemia trait is present
• The combination of HbC trait with alpha-thalassemia is well-documented 3
• This testing is particularly important if MCV remains low after iron repletion

4. Beta-Thalassemia Gene Testing (If Indicated)

Consider HBB gene sequencing if:

• HbA2 remains ≥3.6% after correcting iron deficiency
• Microcytosis persists despite normal iron stores
• Family planning is being considered

Important: Compound mutations involving delta-globin and gamma-globin genes can normalize HbA2 levels even with beta-thalassemia, potentially masking the diagnosis 4. If clinical suspicion remains high despite "normal" HbA2, comprehensive genetic testing including HBD and HBG genes may be warranted.

Clinical Management Algorithm

If anemia is present:

1. Check iron studies first
2. If ferritin <30 μg/L → Treat iron deficiency with oral or IV iron supplementation
3. Recheck CBC and iron studies after 8-12 weeks of iron therapy
4. If microcytosis persists with replete iron stores → Proceed with thalassemia gene testing

If no anemia:

1. HbAC trait alone requires no treatment
2. Provide genetic counseling regarding inheritance pattern
3. Screen partner if family planning is being considered (risk of HbCC or HbSC disease in offspring)

Key Clinical Pitfalls to Avoid

• Do not assume microcytosis is solely due to iron deficiency: Thalassemia trait commonly coexists and will persist after iron repletion 1
• Do not perform unnecessary GI investigation: In premenopausal women with HbAC trait and iron deficiency, menstrual losses are the likely cause; GI workup is generally not warranted unless other red flags are present 1
• Do not overlook family screening: If beta-thalassemia trait is confirmed, partner testing is essential for reproductive counseling 2, 5
• Recognize that HbA2 can be falsely normal: Iron deficiency lowers HbA2, potentially masking beta-thalassemia trait. Always correct iron deficiency before excluding thalassemia 1, 6

Genetic Counseling Considerations

HbAC trait is asymptomatic and requires no treatment, but carries reproductive implications:

• If partner has HbC trait: 25% risk of HbCC disease (mild hemolytic anemia)
• If partner has sickle cell trait: 25% risk of HbSC disease (significant sickling disorder with hemolysis) 5
• If partner has beta-thalassemia trait: Risk of HbC/beta-thalassemia (variable severity)