Saliva testing is an easy and noninvasive way of assessing your patient's hormone status.
Saliva testing 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 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.
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.
