Patients receive their PreDx results in the form of a color-coded bar chart, with their risk level highlighted as green (low), yellow (moderate), or red (high), and a number between one and 10 (the higher the number, the greater their chance of developing diabetes). "The critical thing about the test is that you don't need to be a rocket scientist to understand it, and that means that patients understand it and get motivated to really make changes," says Ed Kersh, the chief of cardiology at St. Luke's Hospital in San Francisco and a clinical professor of medicine at the University of California, San Francisco.

Kersh started using the test about a year ago, and he says the approach has led to healthy changes in weight and blood-glucose levels in over 90 percent of his high-risk patients. "Creating lifestyle change in patients is a very difficult thing--the success rate for diet, exercise, and smoking cessation is down around 10 percent unless they're confronted with significant data," he says.

One physician was so convinced by the PreDx methodology that he developed an entire weight-loss clinic around the concept of the PreDx test. Michael Abou Assaly directs the Health Living Clinic at the Great River Medical Center in Burlington, IA, and has used the test on about 750 patients. He's seen significant lifestyle changes in about three-quarters of his high-risk patients (about 30 percent, he says). "It's been like nothing I've ever seen, as far as a motivating tool," Abou Assaly says.

Richard Bergman, a professor of physiology and biophysics at the Keck School of Medicine at the University of Southern California, specializes in diabetes risk prediction and has developed a clinical method that can measure that risk. But the PreDx test, he says, "is better than anything else you can do without a clinical test," which requires time and money. "The fact that it can be measured from a blood sample and is much less labor-intensive means that it can be used routinely in a doctor's office," says Bergman, who is on the Tethy's scientific advisory board.

Tethys hopes to submit its PreDx research to the FDA for approval sometime in 2011. (Such diagnostic tests don't require FDA regulation, which is how the company has been able to market it so broadly.) In the meantime, they're also working to create similar risk-profile tests for cardiovascular disease and osteoporosis and hope to have the first one, a test for heart-attack risk, ready for market within the next two years.