Over the past 20-30 years numerous
research studies have validated the use of saliva as an analysis medium to
measure the biologically active fraction of steroid hormones in the blood
stream. Saliva is an excellent medium to measure steroids because it is a
natural ultrafiltrate of blood, and steroids not bound by carrier proteins in
the blood freely diffuse into saliva.
Only about 1-10% of the steroids in blood
are in the unbound or free form, and it is this fraction that diffuses into
target tissues of the body, and into saliva. The majority (90-99%) of steroid
hormones in the blood are bound to carrier proteins (cortisol binding globulin
and albumin) and are unavailable to target tissues.
The process of passive
diffusion of non-bound (free) steroid hormones occurs because these small
molecules are of a low molecular weight (less than 40 daltons) and are
relatively nonpolar, thus enabling them to freely diffuse from blood to saliva.
The steroid hormones that have been studied the most extensively in saliva
include estrogens (estradiol, estrone, and estriol), progesterone, androgens (DHEA,
testosterone), and cortisol.
Advantages of Saliva Analysis:
reflects the biologically active (free) fraction of steroids in the
bloodstream unlike blood or urine which measures total levels)|
time more controlled which is critical for baseline testing of hormones with
dirurnal variation and assessment of HRT dosing|
simple, safe, stress free, and painless|
for multiple collections outside of office setting|
stable in saliva at room temperature for weeks|
of saliva to laboratory by regular US mail|
expensive than blood testing|