Spit test could predict life span

http://www.dailymail.co.uk/health/article-3372233/The-spit-test-predict-long-live-Levels-antibody-body-fall-nearer-person-gets-death.html

The spit test that can predict how long you will live: Levels of an antibody in the body fall the nearer a person gets to death

Levels of a particular antibody fall the nearer a person got to death
Testing levels of the antibody could be used to look at overall health
Experts: Saliva tests are much less invasive than blood sampling