Using saliva to detect disease holds promise, but it's not perfected yet

Your saliva is "like a microbial fingerprint," says Purnima Kumar, a spokesperson for the American Dental Association. But it also changes if you take a sip of water or coffee.

Easier than a blood test, saliva tests have the potential to detect cavities, infections and even cancer. But a lack of insurance coverage and other obstacles stand in the way of wider use.

(Image credit: dusanpetkovic)