Salivary cortisol determined by enzyme immunoassay is preferable to serum total cortisol for assessment of dynamic hypothalamic--pituitary--adrenal axis activity.
European Journal of Endocrinology finds that salivary cortisol can be used as a diagnostic tool for Cushing's syndrome and adrenal insufficiency. Thus both hypercortisol and hypocortisol states can be followed using saliva. This statement was using immunoassay. Mass spectroscopy provides even better results
LC-MS/MS overcomes the limitations of immunoassays in hormone testing. LC-MS/MS is the new gold standard with sensitivity, specificity, and ease second to none. LC-MS/MS is the bench science now coming to the practice of medicine.
Opinion publication recommends total Testosterone as primary means of evaluating Testosterone. This recommendation relies on the use of immunoassay techniques which can lack specificity compared to newer LC/MS and GC/MS techniques. The authors did recommend using salivary Testosterone when borderline and SHBG variables play in, which happens to be most clients I see. The best approach is to use both simultaneously to give a more clear physiologic picture to start.
granted, this comes from the American Journal of Primatology; but their conclusion says it all: "we recommend that saliva collection may be the moste effective method of measuring stress reactivity and as the potential to complement behavioral, cognitive, physiologic, and welfare studies".
salivary testing of cortisol proven to be a better test than blood cortisol. Published in Clinical Endocrinology, '05. Salivary cortisol testing is best test to evaluate cortisol levels.