Saliva Hormone Testing vs Blood Testing
The primary hormones tested using saliva are the sex hormones, Estradiol, Progesterone and Testosterone, and the adrenal hormone Cortisol.
The benefits of using saliva versus blood are the following.
- In blood, all sex hormones are either bound to the protein Sex Hormone Binding Globulin, SHBG, or they are detached and referred to as free and available.
- Being detached from SHBG, the free sex hormones can leave the blood stream and travel through lymph fluid to then interact with cells.
- Saliva is lymph so we can, through saliva hormone testing, measure the free sex hormones.
With blood testing, we are measuring the total of each sex hormone, meaning both the bound and the free, so we don’t exactly know how much of the hormone is free.
Using saliva testing we have a much more accurate way of interpreting the available sex hormones.
Saliva Collection
With saliva testing, four samples are collected throughout the day, from morning until evening, which is more accurate than a single blood draw.
For menstruating women, these collections are done on day 19 or 20 of their cycle and the lab’s reference range for each sex hormone is calculated based upon this point of the cycle. Most often the blood draw for sex hormones is random though there are reference ranges for each phase of the cycle.
For post menopause, saliva is collected on any day.
Cortisol & Adrenal Fatigue
In the blood stream, the protein carrier for Cortisol is Transcortin. With sex hormones, there is a pattern of release through the cycle, with Estrogens being high in the beginning and Progesterone higher at the end, but with Cortisol, there is a normal rhythmic pattern of release through a 24-hour period, high in the morning then tapering off through the day.
The only way to know a person’s Cortisol pattern is to collect four saliva samples from the morning until the evening.
And remember, just as with sex hormones, Cortisol blood testing tells us the total Cortisol, both the bound to Transcortin and the free and available.
Obviously, saliva testing with four samples is advantageous since the typical blood test for Cortisol is a single draw. Plus, Cortisol blood results reflect the total cortisol and not the free.
Another factor in assessing blood Cortisol levels is a false elevation of Cortisol due to the needle puncture for the blood draw.
Saliva Collection
Each saliva kit comes with four small plastic collection vials with instructions.
For the analysis of sex hormones, the saliva from each tube collected through the day is homogenized and then analyzed.
For Cortisol, each sample is measured separately and with the information included with the lab requisition, the lab knows the time of day of each collection.
If a person is doing both sex hormones and Cortisol, Cortisol is measured from each tube first and then the saliva is mixed for sex hormone testing.