A sensitive direct enzyme immunoassay for cortisol in plasma and saliva.
A sensitive enzyme immunoassay for cortisol in plasma and saliva without extraction has been developed. An antibody was raised in rabbits against cortisol-3-CMO-BSA and compared with anti-cortisol-21-HS-HSA. The enzyme label was a covalently linked cortisol-horseradish peroxidase conjugate. Solvent extraction was avoided by use of heat denaturation of transcortin and dilution of plasma 1:300. This assay had a limit of detection of 3 fmol/tube and satisfied the standard criteria of accuracy and precision. The test requires only a simple photometer. The normal values of cortisol in plasma and saliva before and after ACTH, dexamethasone or metyrapone application were determined. Saliva, being easily collected by a noninvasive, stress-free technique is an alternative to plasma. The cortisol concentrations were significantly increased in plasma and saliva of patients with Cushing's syndrome and decreased in patients with Addison's disease.
D000224:Addison Disease / Q000097:blood / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000328:Adult; D003480:Cushing Syndrome / Q000097:blood / Q000175:diagnosis / Q000378:metabolism; D003907:Dexamethasone; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000097:blood*; D007124:Immunoenzyme Techniques / Q000592:standards; D012463:Saliva / Q000032:analysis*
D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone