Determination of cortisol in saliva and serum by a luminescence-enhanced enzyme immunoassay.

A new luminescence-enhanced enzyme immunoassay (LEIA) has been developed and validated for the direct measurement of cortisol in saliva and serum. It has been demonstrated that this LEIA has a very good analytical and functional sensitivity. There was a good correlation to a commercial RIA. The assessment of diurnal cortisol profiles of healthy persons are discussed. Cortisol monitoring is indicated in diseases with abnormal glucocorticoid production such as Cushing's syndrome and Addison's disease. Because of the diurnal fluctuation of cortisol levels it is necessary to take several samples for an individual cortisol profile or during dynamic tests like the dexamethasone-suppression or ACTH stimulation. Salivary sample collection is an alternative method without the stress of repeated venipuncture. The measurement of cortisol in saliva is advisable in patients with abnormal cortisol-binding-globulin (CBG) levels such as pregnancy, hypothyroidism, nephrotic syndrome or marked adipositas and during the administration of certain drugs, especially oral contraceptives.