Saliva testing is an easy and noninvasive way of assessing your patients hormone balancing needs, and is proving to be the most reliable medium for measuring hormone levels. Unlike serum tests, saliva testing represents only hormones actively delivered to receptors in the body. Clinically, it is far more relevant to test these bioavailable hormones and provide an accurate reflection of the body’s active hormone levels.
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.