There is now sufficient evidence to show that standard serum (blood) testing protocols cannot quantify low concentrations of hormones in a reliable way. In general, blood measurements only give the total saliva hormone concentration, whereas saliva testing measures the important free, bioavailable, hormone level.
“The measurement of testosterone (T) in plasma or serum, as done in most laboratories, suffers from a number of serious problems.” – Endocrine Society Position Statement
A cursory look at serum & saliva
Research into hormone analysis has shown that, for most purposes involving otherwise healthy individuals, serum (blood) has limited application. Here’s why:
Saliva hormones present in the blood are either completely “bound” to their specific binding globulins, or “free”. At present, most saliva hormone testing is conducted using the traditional method, i.e., by sampling and analysing blood – an invasive and costly procedure.
Let’s look a little deeper;
The bound component is biologically inactive and is considered to be a kind of hormone storage. A mere 5% (as low as 2%) of the total hormones present are “free”, “active” or “bioavailable” and these are responsible for hormone activity in the body. In serum (blood) or plasma testing, the saliva measurement represents the level of the total hormone, including the “bound” component.
This total concentration at best gives only an approximate indication of the bioavailable hormone present in cases of completely healthy and normal patients.
Reliable measurements in hormone testing
The Endocrine Society published an official position statement, including that reliable measurements in serum testing either need an additional extraction step, or need to be completed using chromatographic methods, such as tandem MS or GCMS for testing hormones (sophisticated and very expensive equipment). This casts doubt on the validity of the blood test for free, bioavailable hormones.
Disclaimer: TestoChecker provide saliva hormone test kits in Australia and willingly disclose it’s interest in the popularity of saliva hormone testing. It should also be noted that Serum, Saliva and Hair (as tissue sample types) all have unique advantages. No test specimen type can be considered perfect.
Only a limited number of hormones tested
Saliva as a speciment type has it’s own limitations. Whilst it would be great to be able to test FSH levels (follicule stimulating hormone) for assesment of the health of the hormnones required for conception and during pregnancy, for example, we cannot. Wouldn’t it be great to measure the dopamine hormone using saliva, unfortunatly it won’t happen.
Of the approximate 50 hormones found within the human body, saliva (as a test specimen type) has only proven usefull for around 7 of those.
On the other hand, saliva sampling is non-invasive and can be done anytime, anywhere, and at multiple time points day or night. Provided the proper collection and testing procedure(s) is observed, hormones are tested reliably using saliva as the biological specimen type.
To read more about this important topic see our Blog Post ‘Limitations of Serum AND Saliva for testing hormones‘
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