By Magali Fischer
Steroid analysis using a saliva sample first appeared in the scientific literature more than 40 years ago.1 Now, as then, saliva sampling presents an attractive alternative to blood testing because it is non-invasive, easily repeatable, can be performed in settings that may not be conducive to blood sampling, and is less stressful and more convenient for patients.
Saliva diagnostics - a valuable, needle-free alternative for hormone testing.
Saliva contains various hormones and other chemicals that can serve as direct indicators or indirect biomarkers of human health, biochemical imbalances, and a variety of disease states. Saliva-based diagnostic assays are available to detect and measure medically important compounds such as steroids, including the adrenal hormones cortisol and dehydroepiandrosterone (DHEA), the sex hormones estradiol, progesterone, and testosterone, as well as melatonin, alpha amylase, and IgA.
In recent years the use of saliva testing has increased, particularly in rapidly advancing fields such as psychobiology, occupational medicine, functional medicine, pharmacology, and sports medicine.1 Importantly, these and other medical disciplines can benefit not only from the advantages of saliva testing listed above -- it is easy, painless, and can be done virtually anytime, anywhere -- but also from the fact that saliva measurements reflect biologically active steroid levels.2 Most steroid hormones in the bloodstream are bound to carrier proteins and are metabolically inactive. Only a small amount of any hormone in the blood is unbound and able to enter cells and affect their function. Therefore, standard blood tests do not measure bioavailable hormone levels.
In contrast, only free, unbound hormones leave the bloodstream and make their way into the saliva. Thus, saliva testing provides a measure of biologically active hormones. Furthermore, established methods of saliva testing have proven to be highly accurate.2 As saliva contains much lower concentrations of hormones than are in blood-, a mere 1-5% of total hormone levels, saliva-based assays need to be extremely sensitive to measure these very low levels.
The hormone levels in your saliva say a lot about you, your health and, for example, how you manage stress. Cortisol, which is present in saliva, is often called the "stress hormone." When the body is under stress, whether physical, mental, or emotional, cortisol levels rise. 3 This, together with the actions of other stress-related hormones such as DHEA (the anti-stress hormone), affects various bodily functions including regulation of the immune system, sleep, mood, fat and protein metabolism. Chronic stress can lead to an imbalance in the levels of cortisol and DHEA and the risk of adrenal dysfunction.
In the healthy body, cortisol levels are at their highest in the morning and fall throughout the day, rising again after midnight. Stress testing using salivary cortisol measurements is an increasingly common method of monitoring for worker burnout in occupational medicine.
Sleep disorders are another important occupational health concern, especially among shift workers. Melatonin, which promotes night-time sleep, rises and falls during the day, like cortisol, but in a different pattern. Measuring the saliva levels of both melatonin and cortisol is a useful approach for evaluating an individual's circadian rhythms and diagnosing sleep disorders.
Another valuable application of saliva diagnostics is the testing of hormone levels in peri-menopausal women to guide the use of hormone replacement therapy (HRT). Genova Diagnostics (www.gdx.net) and GanzImmun Diagnostics AG (www.ganzimmun.de), for example, have developed optimal saliva collection strategies and assay methods to test for sex hormones including 17ß-estradiol, estriol, progesterone, and testosterone. Accurate measurements of the biologically active components of these hormones present in saliva can help clinicians adjust HRT levels to administer the proper balance of hormones.
In the field of sports medicine, the ease and non-invasiveness of saliva testing, which can be performed at a training site without the need for medical personnel, makes it an increasingly attractive option. Measuring saliva concentrations of cortisol, DHEA, and testosterone, for example, and comparing them at different stages of exertion can help athletes achieve their peak level of performance leading up to a competitive event and avoid overtraining and fatigue.
In the hospital setting, endocrinologists may rely on saliva measurements to determine the levels of a variety of hormones to diagnose the cause of clinical symptoms or monitor a disorder and the effectiveness of treatment. Salivary cortisol levels, for example, are an established indicator of adrenal function. Saliva testing of cortisol is a well-accepted method of diagnosing Cushing's disease (hypercortisolism).4 Measurement of testosterone in saliva provides a good assessment of androgenic status.5
Saliva diagnostics is growing at a rate of about 10% per year globally. This growth is marked by an ever-broadening range of clinical applications, a deepening knowledge base, and advances in assay technology, detection techniques, and automation. Continuing progress and increased adoption and application of saliva-based hormone testing will further support its value as an alternative to traditional blood-based diagnostics.
Download our brochure on saliva diagnostics to discover the value in saliva based hormone testing.