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Vitamin B12 deficiency — RCPSC IM MCQ

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ModerateHematologyVitamin B12 deficiencyRCPSC IM

A 70-year-old woman has macrocytic anaemia, glossitis, numbness in both feet, and impaired vibration sense. Hemoglobin is 82 g/L, MCV 118 fL, leukocytes are low, and platelets are low. Serum B12 is borderline. What is the most appropriate investigation?

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Correct answer: E — Methylmalonic acid and intrinsic factor antibody testing

Macrocytosis with cytopenias and neurologic signs suggests vitamin B12 deficiency. Methylmalonic acid helps confirm deficiency, and intrinsic factor antibody assesses pernicious anaemia.

Reference: Canadian hematology practice guidance