Functional testing explains the dynamic interrelationship of physiological systems, thus creating a more comprehensive understanding of one’s health. This type of test is designed to identify the cause of the problem, which can often be due to environmental, inflammatory or nutritional stress. Discovering these causes is a corner stone in providing successful health care by designing the proper treatment approach for individuals.

Saliva holds the key to determining the internal milieu. Just as an ophthalmologist looks onto the retina and has a window of the inner workings of the body, watching blood cells travel through the capillaries, so too are physicians fortunate to have a non-invasive medium to accurately measure the hormones of the body. It is well documented that saliva is the preferred method of hormone evaluation, over serum testing.

There are three critical issues involved in testing hormones in any individual: to report a hormone’s free fraction only, to report the hormone level found in the tissues, and that the lab is dynamically involved with the testing and tests each batch for quality assurance.

Hormones are found in the human serum in two forms, free and bound. The free or active form, which makes up 1-5% of the hormones in the serum, is responsible for hormone receptor activation. The bound or inactive form, comprising 95 to 99% of the hormones in the serum, is waiting to be released from binding proteins. Until that time, this bound form does not elicit an effect on the body.

When determining the course of treatment for hormone imbalance symptoms and illnesses, knowing the level of active hormones in the tissues is necessary for making accurate medical recommendations. To know tissue levels, one has to study the level of hormones from a tissue biopsy, which is not practical, or study a readily available fluid that is known to have the same concentration of bioavailable hormones as the tissues. Differentiating or filtering the free fraction from the bound hormone is essential and it is done naturally and efficiently in the formation of saliva. As blood passes through salivary glands, free “unbound” and weakly bound (low affinity binding protein) forms of hormones diffuse through the salivary gland epithelium into the saliva. As in other clearing organs, membrane transfer occurs in both directions; it is passive for most substances and equilibrium is governed by the transmembrane concentration gradient. Thus, saliva levels reflect the free concentration of hormones.

Test results that include the quantity of bound hormone are not only irrelevant but may vastly shift a patient’s treatment. Reporting hormone levels in samples from both blood and urine do not isolate the active hormones and do not correlate with the level of hormones in the tissues. Therefore, clinicians frequently overlook serum or urine hormone test results when they seemingly do not match up with a patient’s medical needs.

Evaluating hormone levels of the saliva fulfills the need for reporting both the bioavailable hormone and the concentration of hormones found in the tissues.

Measuring salivary hormones is technically challenging due to the small amount of bioavailable hormone in the saliva, 2-5% of the serum hormone level. Measuring these small concentrations requires absolute accuracy. Fortunately, salivary hormones are stable for up to two to three weeks after specimen collection. The science behind saliva testing requires choosing highly reliable test materials, constant data analysis, including control specimens with every test run, calibrating the materials to World Health Organization’s strict standards, and validating results by sending blinded specimens out to reference labs for confirmation.

Saliva testing is practical and convenient, and has been done commercially in the U.S. at Diagnos-Techs’ Lab since 1987.

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Hofman LF. 2001 May; 131(5): 16215-55

Clinical Chemistry 101-129 1752-1756