Saliva could provide an alternative for some diagnostic tests
When I was a kid, my best friend Ben and I used to compete at great lengths to make each other laugh. One time, I made Ben laugh so hard that he actually spit, and some of his saliva landed on my arm. I thought that was gross and recoiled in horror, but Ben just laughed even harder. "It's okay, silly," he said. "Spit is just water."
If only he had known what spit scientists know now, he wouldn't have been so flippant. Besides the water, saliva is swimming with bacteria, viruses, DNA, RNA, proteins, fatty acids, and hundreds of other molecules. Medical scientists are taking advantage of these components to develop tests for myriad health problems. Saliva tests for cancer,