Saliva testing has been scientifically established as a highly accurate medium for measuring hormone levels equivalent to conventional blood testing. In fact, in 2012 alone over 600 hundred studies were published in peer-reviewed journals using saliva analysis of hormones.
Findings of note include:
• Saliva testosterone levels shows excellent correlation
to free serum testosterone in men
• Estradiol and progesterone saliva/serum correlations are consistently observed throughout pre- and postmenopausal concentration ranges
• Salivary cortisol is the method of choice for Cushing’s diagnosis and stress assessment
• Saliva estradiol/progesterone is effective for
monitoring of menstrual cycles and frequently used in fertility studies
Saliva testing is used for measuring hormones like cortisol, estrogen and testosterone, and its non-invasive collection asks patients to spit into a plastic tube. This sampling method allows patients to collect saliva at home at specific times, which is important for accurately measuring hormone levels.
Why do we test hormones in saliva? Steroid hormones in the bloodstream are 95-99% bound to carrier proteins, and in this form are unavailable to target tissues. Saliva testing measures the amount of hormone available to target tissues – the bioavailable amount. For this reason, saliva testing better relates to specific symptoms of excess or deficiency, and is a good option for monitoring hormone therapy.
ZRT is one of the first labs to measure hormones in saliva, and helped establish the method that made saliva hormone testing commercially viable for health care providers and patients around the globe.
Ample scientific evidence demonstrates that saliva testing is as accurate as serum. It has the additional advantage of being convenient and non-invasive.
Ranges Adjusted for Supplementation
Unlike other labs, it is not necessary to stop hormone supplementation to use ZRT’s testing because we have ranges adjusted for age, menstrual status and supplementation types. This is the ideal method for tracking the effectiveness of hormone treatments.
ZRT does not pool patient samples, meaning that we don’t mix multiple daily samples together to get an average hormone level. Instead we measure hormones from a single morning sample, which represents the peak of daily hormone production – the optimal time to measure.
ZRT is the only lab to perform an extraction process for saliva testing, which separates hormones from background contamination. This is the only way to assure accurate test results for low-concentration hormones such as estradiol.
Setting Industry Standards
ZRT initiated and manages the industry-wide standards program called the Saliva Proficiency Inter-laboratory Testing Program – which enables laboratories to regularly evaluate and improve saliva testing accuracy.