The MKSAP Challenge
Clinical scenario
A 62-year-old woman is evaluated because of abnormal results on chest radiograph. She smokes one pack of cigarettes per day, with a 50-pack-year history. She has a morning cough productive of small amounts of yellow sputum. She has hypertension, for which she takes metoprolol, and type 2 diabetes mellitus, which is managed with diet and metformin therapy.
Her body mass index is 30. Her blood pressure is 145/90 mm Hg. Chest radiograph shows a 1.5 cm nodule in the left upper lobe; no previous radiographs are available for comparison.
Which of the following should be measured before sending this patient for a positron emission tomography scan to evaluate the nodule?
A. Serum sodium.
B. Blood pressure.
C. Serum creatinine.
D. Serum glucose.

