Review Question - QID 108271

A 75-year-old woman with a history of Hashimoto's disease on thyroid replacement and hypertension presents to your outpatient clinic for fatigue that has progressively worsened over the last year. She has also experienced a fall a few days prior to presentation due to "not knowing where I was stepping when the lights are off." She reports that her husband has noticed she has become more forgetful lately, such as not remember she is expecting visitors or turning the stove off after she finished cooking. She denies fevers, chills, weight loss, and night sweats. She has no chest pain, shortness of breath, constipation, diarrhea, dysuria, heat or cold intolerance. Her temperature is 99.5 deg F (37.5 deg C), blood pressure is 103/72 mmHg, pulse is 76/min, respirations are 12/min. On physical examination, she has a slightly large tongue. She has decreased vibration and proprioception sense in her bilateral lower extremities. She also has a positive Romberg test. Her lab results demonstrate a normal TSH. A peripheral blood smear shows the following: (Figure A). Which of the following lab results would be most consistent with the patient’s clinical presentation?