A 29-year-old woman at 8 weeks’ gestation comes to the obstetrician for her first prenatal visit. She has no past medical history and her pregnancy has been uncomplicated. Laboratory studies show:
Hemoglobin: 10 mg/dL
Mean corpuscular volume: 70 μm3
Serum ferritin: 90 ng/mL
Serum iron 130 μg/dL
Which of the following is the most appropriate next step in diagnosis?
α-globin DNA testing
Hemoglobin electrophoresis
Hemoglobin solubility testing
Measurement of serum folate
Measurement of serum cyanocobalamin
