What is the difference between saliva testing and serum (blood) testing?
Saliva tests measure “free” hormones (2-5% of the hormones in a person’s body), which are the hormones that are available to go to work for you, stimulating receptor cells and carrying out the tasks they are designed to perform. In contrast, serum testing generally measures the “total” hormones, which includes those hormones already bound to protein and unavailable for your cells to use.