A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 27-year-old African-American woman, gravida 1, para 0, at 11 weeks' gestation comes to her physician for a prenatal visit. She feels more fatigued than usual but has no other symptoms. She has no history of serious illness. She takes no medications. Her mother has systemic lupus erythematosus. Her temperature is 37.2°C (98.9°F), pulse is 80/min, respirations are 18/min, and blood pressure is 120/75 mm Hg. Examination shows no abnormalities. Laboratory studies show:
Hemoglobin 9.2 g/dL
Hematocrit 27.5%
Leukocyte count 6,000/mm3
Platelet Count 180,000/mm3
MCV 74 μm3
MCH 24 pg/cell
Serum
Na+ 138 mEq/L
K+ 4.5 mEq/L
Cl- 100 mEq/L
HCO3- 25 mEq/L
Urea Nitrogen 15 mg/dL
Creatinine 1.0 mg/dL
Total Bilirubin 0.4 mg/dL
Iron 67 U/L
Ferritin 98 ng/mL
Which of the following is the most appropriate next step in management?"
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A
Measure anticardiolipin antibody titersIncorrect. Anticardiolipin antibodies are relevant in antiphospholipid syndrome with recurrent pregnancy loss or thrombosis — not in evaluating microcytic anemia with normal iron studies.
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B
AmniocentesisIncorrect. Amniocentesis is invasive prenatal testing and is not the next step in evaluating maternal microcytic anemia.
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C
Perform direct Coombs testIncorrect. Direct Coombs evaluates immune-mediated hemolytic anemia, which would present with normocytic or macrocytic anemia and elevated indirect bilirubin — not this microcytic picture.
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D
Hemoglobin electrophoresisCorrect. Hemoglobin electrophoresis identifies thalassemia trait or hemoglobinopathy in patients with microcytic anemia and normal iron studies, enabling appropriate genetic counseling in pregnancy.
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E
Iron supplementation trialIncorrect. Empiric iron is appropriate for iron-deficiency anemia, but this patient's normal ferritin and serum iron exclude iron deficiency; hemoglobin electrophoresis is needed to evaluate for thalassemia trait.
↑ Tap an answer to reveal the reasoning
Answer: D. An African-American pregnant woman with a mild microcytic anemia (MCV 74), normal iron studies (iron 67, ferritin 98 — adequate), and normal renal function has a microcytic anemia that is NOT iron deficiency. With normal iron stores, the next step is hemoglobin electrophoresis to evaluate for thalassemia trait or hemoglobinopathy. Beta-thalassemia minor shows elevated HbA2 and sometimes HbF; alpha-thalassemia trait shows a normal electrophoresis but is suggested by exclusion. Sickle cell trait (HbAS) would also be detected.
Identifying thalassemia trait or sickle trait in pregnancy is important for genetic counseling — if the father also carries an abnormal hemoglobin, the fetus may be at risk for major disease (e.g., hemoglobin Bart's hydrops fetalis from alpha thalassemia, or sickle cell disease, or beta-thalassemia major). The father can then be tested and prenatal diagnosis offered.
Clinical pearl: in any pregnant patient — especially of African, Mediterranean, Middle Eastern, or Southeast Asian descent — with microcytic anemia and normal iron studies, get hemoglobin electrophoresis. Don't blindly treat with iron when iron stores are already replete.
**Why each option:**
**A.** Anticardiolipin antibodies are relevant in antiphospholipid syndrome with recurrent pregnancy loss or thrombosis — not in evaluating microcytic anemia with normal iron studies.
**B.** Amniocentesis is invasive prenatal testing and is not the next step in evaluating maternal microcytic anemia.
**C.** Direct Coombs evaluates immune-mediated hemolytic anemia, which would present with normocytic or macrocytic anemia and elevated indirect bilirubin — not this microcytic picture.
**D.** Hemoglobin electrophoresis identifies thalassemia trait or hemoglobinopathy in patients with microcytic anemia and normal iron studies, enabling appropriate genetic counseling in pregnancy.