Figure 1. Algorithm for Testing Patients Suspected of Having
Cushing's Syndrome (CS)
Cushing's Syndrome suspected:
(consider endocrinologist consultation)
Exclude exogenous glucocorticoid
exposure
Perform one of the following tests:
24-h UFC (≥2 tests) Overnight
1-mg DST
Late night salivary
cortisol (≥2 tests)
• Consider caveats for each test (see text)
• Use 48-h, 2-mg DST in certain populations (see text)
ANY ABNORMAL
RESULT
Normal (CS unlikely)
Exclude physiologic causes of hypercortisolism (Table 2)
Consult endocrinologist
Cushing's Syndrome
Perform 1 or 2 other studies shown above
Suggest consider repeating the abnormal study
Suggest Dex-CRH or midnight serum cortisol in certain populations
(see text)
ABNORMAL
Discrepant
(Suggest additional evaluation)
Normal (CS unlikely)
All statements are recommendations except for those prefaced by "suggest." Diagnostic criteria that
suggest Cushing's syndrome are: UFC greater than the normal range for the assay, serum cortisol
greater than 1.8 μg/dl (50 nmol/liter) aer 1 mg dexamethasone (1-mg DST), and late-night salivary
cortisol greater than 145 ng/dl (4 nmol/liter).
