The Endocrine Society has published clinical practice guidelines for the diagnosis of Cushing's syndrome. The guidelines aim to help clinicians identify patients with this condition, which is characterized by prolonged exposure to high levels of cortisol. The guidelines emphasize the importance of excluding exogenous glucocorticoid use before testing. They recommend initial testing with one of several tests, including urine free cortisol, late-night salivary cortisol, and dexamethasone suppression tests. Patients with abnormal results should be referred to an endocrinologist for further evaluation. If results are abnormal, additional tests such as the dexamethasone-CRH test or midnight serum cortisol test may be used. Patients with concordant abnormal results should undergo testing to determine the cause of Cushing's syndrome, while those with concordant normal results do not require further evaluation. The guidelines also address special populations, such as pregnant women, patients with epilepsy, and those with renal failure, and provide specific testing recommendations for these groups. The guidelines are based on systematic reviews of evidence and expert consensus, and they emphasize the importance of using tests with high diagnostic accuracy. The guidelines also highlight the need for careful interpretation of test results, considering factors such as the patient's clinical presentation and the possibility of false positives. Overall, the guidelines aim to improve the accuracy and efficiency of diagnosing Cushing's syndrome.The Endocrine Society has published clinical practice guidelines for the diagnosis of Cushing's syndrome. The guidelines aim to help clinicians identify patients with this condition, which is characterized by prolonged exposure to high levels of cortisol. The guidelines emphasize the importance of excluding exogenous glucocorticoid use before testing. They recommend initial testing with one of several tests, including urine free cortisol, late-night salivary cortisol, and dexamethasone suppression tests. Patients with abnormal results should be referred to an endocrinologist for further evaluation. If results are abnormal, additional tests such as the dexamethasone-CRH test or midnight serum cortisol test may be used. Patients with concordant abnormal results should undergo testing to determine the cause of Cushing's syndrome, while those with concordant normal results do not require further evaluation. The guidelines also address special populations, such as pregnant women, patients with epilepsy, and those with renal failure, and provide specific testing recommendations for these groups. The guidelines are based on systematic reviews of evidence and expert consensus, and they emphasize the importance of using tests with high diagnostic accuracy. The guidelines also highlight the need for careful interpretation of test results, considering factors such as the patient's clinical presentation and the possibility of false positives. Overall, the guidelines aim to improve the accuracy and efficiency of diagnosing Cushing's syndrome.