Screening for Cushing's syndrome using early morning urine samples.

Urinary free 11-hydroxycorticosteroid/creatinine ratios (UFC/Cr)were determined in early morning urine samples from 138 obese subjects attending endocrine clinics in the Glasgow area. The majority of patients (128) had UFC/Cr ratios within the normal range for non-obese subjects (5-55 mumol/mol). Of those with elevated UFC/Cr ratios, further investigations of the hypothalamic-pituitary-adrenal axis confirmed a diagnosis of Cushing's syndrome due to bilateral adrenal hyperplasia in six of the cases and adrenal tumours in a further two patients. In the remaining two patients there was evidence of intermittent adrenal hyperactivity with inconsistent responses to insulin-induced hypoglycaemia tests.