List three tests used in the diagnosis of Cushing’s syndrome (at least 2/3 should be abnormal to make the diagnosis).
Increased production of cortisol: increased 24 hour urine free cortisol
Lack of suppression: 1 mg dexamethasone suppression test (patient takes 1 mg of dexamethasone between 11 pm- midnight, 8 AM serum cortisol does not suppress to <50 nmol/L (50-140 nmol/L “grey zone”)
Lack of diurnal variation: elevated serum or salivary midnight cortisol
