A 29-year-old man comes to the physician because of a 1-month history of fatigue. He has lost 5 pounds during this time. Vitals are normal. Serum studies are as follows:
K+ 5.5 mEq/L
Na+ 133 mEq/L
HCO3– 21 mEq/L
Eosinophils 25% (NR 1-5%)
Which of the following is the most appropriate next step in diagnosis?
ACTH stimulation test
Antinuclear antibody
Dexamethasone suppression test
Stool antigen
Stool culture
Stool microscopy for ova and parasites
