Dr. Craig Reese, DC, PC
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There is some misunderstanding about which testing is best and I though this article explained it well.
Labrix Clinical Services, Inc
www.labrix.com
Saliva vs. Serum vs. Urine: Which is best for hormone testing?
There are three established ways of measuring hormone levels: saliva, serum and urine. But how do you choose which medium to use when it is necessary to test your patient's hormones?
Saliva vs. Serum
Saliva testing is proving to be the most reliable medium for measuring cortisol and sex hormone levels. Saliva accurately represents the amount of hormone delivered to receptors in the body, unlike serum which represents hormone levels that may or may not be delivered to receptors in the body. Clinically, it is far more relevant to test the amount of hormone delivered to the tissue receptors, as this is a reflection of the active hormone levels in the body.
The hormones in blood exist in one of two forms: free (5%) or protein bound (95%). While 95% of the hormones in the body are bound to protein carriers, it is only 5% of these hormones that are free and biologically active.
Saliva measures the free, bioavailable hormone levels in the body. When blood is filtered through the salivary glands, the protein 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, 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.
In a healthy person, cortisol levels are naturally highest in the morning and gradually recede throughout the day. Saliva testing allows easy collection over the course of an entire day so that diurnal cortisol levels can be assessed. In addition, saliva testing is preferable to serum testing as studies have shown that the stress of venipuncture can greatly alter cortisol levels; plasma cortisol levels after a difficult blood draw can be misleading.
Perhaps most importantly, only saliva testing can measure 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), with no parallel increase seen in serum levels. Therefore, serum testing cannot be used to monitor topical hormone therapy.
Saliva pros:
- The most reliable measure of free, bioavailable hormones
- The only way to measure topically dosed hormones
- Non-invasive collection. Most convenient for multiple collections over the course of one day.
Saliva cons:
- Cannot measure protein hormones such as insulin or thyroid hormones.
Saliva vs. Urine
Why saliva instead of urine for measuring hormones? When deciding how to assess hormone levels in a patient it is important to establish a methodology that will allow for ongoing testing and monitoring. Urine testing cannot measure hormones directly...just the metabolites of hormones, so it is not a sufficiently accurate tool for direct measurement of assessing deficiencies and subsequent treatment.
In addition, once a patient is started on a prescription of topical hormones, the adjusted hormone levels cannot be accurately assessed through urine or blood - only saliva. This is because blood and urine do not show bioavailable hormone levels. Saliva, on the other hand, is a proven method for adjusting and monitoring therapy as it reflects changes in hormone levels when a patient is on a topical hormone replacement.
Providers who decide to use urine testing will often find that it takes a long time to get prescription rates correct and existing symptoms may continue while new symptoms may appear.
Urine pros:
- Measures hormone metabolites that are not measurable in saliva.
- Allows insight into liver function by assessment of Phase-1 and Phase-2 metabolites
Urine cons:
- Cannot measure the circadian fluctuations of cortisol
- Cannot measure bioavailable hormone levels
- Unable to effectively monitor topically dosed hormones, which can lead to overdosing
It is important to understand the benefits and limitations of measuring
hormone levels in different testing media. If measuring bioidentical
hormone levels, diurnal cortisol patterns, or monitoring your patient's
response to transdermal hormone therapies is your goal, then saliva testing
is likely the right choice for you.
The one thing they didn’t mention was cost. The saliva tests usually cost less than blood or urine. We have the kits for all the saliva tests for free and then you pay the lab directly, not us, for the test.
Office News
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