Saliva Testing of Testosterone

I wanted to get everyone's input on Saliva testing of Testosterone. My current doctor insists on its usage (yet does serum testing for DHT) and although my dosage didn't change, my testosterone levels came back five times higher than three months ago using the saliva tests. This has led me to look further into their credibility.

What are your thoughts/experiences with saliva testing?

The company that does the testing is called Labrix. On their website, they state the reason to use saliva testing as--

Protein bound hormones do not fit the 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. Saliva testing measures the bioavailable hormone - the clinically relevant portion delivered to the receptors in the tissues of the body.

I think by my post, you can tell I'm hypothesizing that Saliva testing is not an appropriate way to monitor testosterone levels. I'm open to changing my mind.

Here is the study that Labrix cites as evidence of the efficacy of saliva testing: http://www.researchgate.net/publica...one_as_a_screening_test_for_male_hypogonadism

The issue is that almost all of the medical literature is based on serum levels.

It is not that saliva tests are invalid, it is that there is no way to correlate saliva levels to effective treatment. When the pharmaceutical companies test testosterone drugs (or should I say delivery systems) they always use serum levels to establish efficacy.

Maybe your doctor has had success with saliva testing, but there is no way to compare those results with what the rest of the world does.

Yeah Harry, I tend to agree on the comparability issue. I appreciate your response. Upon researching further, there are many variables that can impact a saliva test and if not done in identical situations (proper temperature, food intake, etc.) then tests can vary. I felt like my testing conditions were consistent but something is off for my results to come back five times higher than the previous test.

I don't want to insult my doctor by insisting upon the bloodwork, but if I come at it from a "comparability" standpoint, he should understand.