Megaloblastic anemia

A 35-year-old woman presents to her provider’s office for evaluation of fatigue and exercise intolerance that began two months ago. Past medical history is notable for Crohn disease diagnosed eight-years ago. She is taking mesalamine but reports frequent “flare-ups.” The patient consumes 3-4 glasses of wine per week. Her temperature is 36.9°C (98.4°F), blood pressure is 123/76 mmHg, pulse is 75/min, and respiratory rate is 12/min. The patient has conjunctival pallor. Cardiac, pulmonary, and abdominal examinations are non-contributory. Neurological examination reveals decreased proprioception and vibratory sensation in the lower extremities. Complete blood count reveals a hemoglobin of 8.8 g/dL (reference range: 12-16 g/dL) and a mean corpuscular volume (MCV) of 115 µm³ (reference range: 80-100 µm³). Which of the following findings would be most likely present in this patient?