24-Hour Urine Cortisol Excretion Assessment Test

The 24-Hour Urine Cortisol Excretion Assessment Test measures the total amount of the hormone cortisol excreted through urine over a full 24-hour period. Cortisol—often called the “stress hormone”—is produced by the adrenal glands and is vital for regulating metabolism, immune responses, blood pressure, and stress adaptation. By collecting all urine over a day, this test captures fluctuations in cortisol production and provides a comprehensive view of adrenal and hypothalamic–pituitary–adrenal (HPA) axis function. It is commonly used to detect disorders such as Cushing’s syndrome (when cortisol is too high) and Addison’s disease (when cortisol is too low), as well as to monitor treatment effectiveness in these conditions. Proper preparation — including collecting all urine in the specified timeframe, avoiding certain medications, and following storage instructions — helps ensure accurate and clinically meaningful results.