From the Daily Mail (U.K.):

A simple saliva test could help doctors identify patients most at risk of a life-threatening stroke.

New research shows that high levels of the hormone cortisol in saliva are directly linked to the build-up of fatty deposits in arteries carrying blood to the brain.

When these deposits - called plaques - break loose, they can cause a blockage that starves the brain of blood and oxygen.

Research published in the Journal of Clinical Endocrinology and Metabolism suggests many strokes could be prevented if doctors routinely tested patients' saliva.

Strokes are the third most common cause of death in England and Wales, after heart disease and cancer. They occur when a clot cuts off the blood supply to the brain.

Clots are often caused by fatty deposits that get dislodged and travel towards the brain. Once they get into smaller blood vessels in the skull, they cause a blockage.

In the latest study, experts at the Erasmus Medical Centre in Rotterdam, Holland, and the Technical University of Dresden in Germany tested volunteers to see if cortisol levels in their saliva pointed to diseased arteries.

Each volunteer provided four saliva samples throughout the course of one day and underwent ultrasound tests to check for plaque deposits in their carotid arteries (in the neck).

The results showed those with the highest cortisol levels also had the largest build-up of plaques.

From UPI.com:

U.S. scientists say they're using DNA extracted from saliva to customize prescriptions and solve dosing problems that often confound doctors and patients.

By using DNA to customize a prescription, researchers at Temple University's School of Pharmacy hope to prevent adverse drug reactions. At the top of the list of problem drugs is warfarin (Coumadin), the most widely prescribed anticoagulant.

The researchers say they're trying to find the correlation between genotypes and the correct dosage of warfarin. By collecting saliva samples and extracting DNA, the scientists can look for variances in genetic clues that make people metabolize the same drug in very different ways.

"Our findings have confirmed there is a genetic variance of certain genotypes that correlate to how these participants respond to this drug," said Associate Professor Nima Patel, one of the investigators. "So, if you have this genotype, we can conclude what your risks may be, based on your DNA."

That would allow doctors to prescribe the correct dosage of warfarin and decrease the risk of adverse drug reactions.