Pitfalls in the diagnosis of central adrenal insufficiency in children.

The diagnosis of central adrenal insufficiency relies heavily on laboratory testing of cortisol levels in the systemic circulation. The lack of cortisol assay standardization challenges the reliability of dynamic tests of the hypothalamic-pituitary adrenal axis. Although the insulin-induced hypoglycemia or metyrapone tests remain the accepted standards for evaluating central adrenal insufficiency in children their associated risks and inconvenience make them unattractive for routine use. Corticotropin testing is an effective first step to evaluate for chronic central adrenal insufficiency for children older than 2 years who are ambulatory, have normal sleep-wake cycle and normal serum protein levels. The low-dose (1 microg) corticotropin test may be superior to standard-dose (250 mcg) for patients with suspected hypothalamic-pituitary disease.