Why is saliva testing preferred over blood testing when testing for cortisol levels?


Q: Why is saliva testing preferred over blood testing when testing for cortisol levels?

A: Saliva testing is better for cortisol levels because it checks the available or free cortisol. This is the cortisol that is bio available. Serum (blood) test measures both available and not available (binded) cortisol. It is therefore not specific.