The biochemical measure we recommend for monitoring cortisol levels is early morning serum cortisol. This is based on the following: (a) as discussed, this is the test most commonly utilized to evaluate surgical success and employing the same method ensures consistency over time, thereby providing traceable changes, and (b) it is our opinion that this is a convenient test as the patient needs only to visit the clinic to have blood drawn. Alternatively, urinary free cortisol (UFC) measurements, the most commonly used test for diagnosis of hypercortisolism, can also be used. Although assessments such as ACTH levels, CRH stimulation test, dexamethasone suppression test, and desmopressin stimulation test may be used, they are less convenient: ACTH degrades quickly and sample collection needs to be handled with great care; CRH and desmopressin stimulation tests require intravenous administration, and the dexamethasone suppression test requires the patient to take a dose of the glucocorticoid late at night and return to the clinic the next morning to have their blood drawn [42]. Although late-night salivary cortisol is useful for the screening and diagnosis of patients with CD [43], it has not been extensively studied in post-surgical patients and is therefore not currently recommended over morning serum cortisol [5].