How accurate is saliva testing compared to blood and urine testing?
Saliva testing has been used in scientific testing for decades and has been shown to be highly accurate. It is the most reliable way to measure free, bio-available hormone activity (Hormones actually doing their job at the cell level). Standard blood and urine tests do not measure bio-available hormone levels. Numerous scientific studies have shown a strong correlation between the levels of steroid hormones in the blood stream and the bio-available levels of steroid hormones in saliva. The World Health Organization has used this method of hormone testing in worldwide comparisons of hormone levels among women living in industrialized vs. non-industrialized countries. In addition, saliva hormone testing more accurately reflects tissue uptake and response of hormones delivered through the skin in creams, gels, or patches than blood or urine tests. http://www.zrtlab.com/Page.aspx?hid=490
In Dr. John Lee’s book, “Hormone Balance Made Simple”, he states that, “At any given time most of the hormones in your body are unusable—tightly bound to proteins in the bloodstream. Only 1 to 2 percent of hormones escape the binding proteins and are free, or bio-available, to enter tissues throughout the body.” He goes on to say, “conventional blood tests measure only the total level of hormones in the blood stream. This is like trying to balance your cheque book without knowing what cheques have been paid out”. By collecting saliva (one of the tissues that bio-available hormones enter is the saliva gland), and measuring its level of hormones, it is possible to determine how much hormone is available to other tissues.
Saliva testing is an easy and non-invasive way of assessing hormone status and balancing needs and is proving to be the most reliable medium for measuring hormone levels.
Appreciating the reliability of saliva testing is based on understanding the difference between steroid hormones in saliva and serum. This difference is based on whether or not the hormones are bound to proteins in the medium used for testing. The majority of hormones exist in one of two forms: free (5%) or protein bound (95%). It is only the free hormones that are biologically active, or bio-available, and available for delivery to receptors in the body. Those which are protein bound do not fit those receptors and are considered non-bioavailable. When blood is filtered through the salivary glands, the bound hormone components are too large to pass through the cell membranes. Only the unbound hormones pass through and into the saliva. What is measured in the saliva is the bioavailable hormone, the clinically relevant portion which will be delivered to the receptors in the tissues of the body.
Salivary hormone levels are expected to be much lower than serum levels, as only the unbound hormones are being measured. When health care providers measure serum hormone levels and prescribe hormone replacement therapy based on those results, patients are often overdosed. If the patients are then tested using saliva, the results are extraordinarily high, and confusion results from a lack of correlation between the two methods.
This discrepancy becomes especially important when monitoring topical, or transdermal, hormone therapy. Studies show that this method of delivery results in increased tissue hormone levels (thus measurable in saliva), but no parallel increase in serum levels. Therefore, serum testing cannot be used to monitor topical hormone therapy.
Hormone Balance Made Simple: The Essential How-to Guide to Symptoms, Dosage, Timing and More, John R. Lee, M.D. and Virginia Hopkins, Aug. 2006
Saliva Measures the “Unbound" Biologically Active or Free Hormone Levels in the Body:
When blood is filtered through the salivary glands, the bound hormone components are too large to pass through the cell membranes of the salivary glands. Only the unbound hormones pass through and into the saliva. What is measured in the saliva is considered the “free", or bioavailable hormone, that which will be delivered to the receptors in the tissues of the body.
Serum Measures the “Protein Bound" Biologically Inactive Hormone Levels in the Body:
In order for steroid hormones to be detected in serum, they must be bound to circulating proteins. In this bound state, they are unable to fit into receptors in the body, and therefore will not be delivered to tissues. They are considered inactive, or non-bioavailable.
Only Saliva Testing Measures Topically Dosed Hormones:
The discrepancy between free and protein bound hormones becomes especially important when monitoring topical, or transdermal, hormone therapy. Studies show that this method of delivery results in increased tissue hormone levels (thus measurable in saliva), but no parallel increase in serum levels. Therefore, serum testing cannot be used to monitor topical hormone therapy.
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