Type 2 diabetes mellitus, also known as adult-onset diabetes, is a common disease that interferes with the body's ability to use sugar, resulting in high levels in the blood. Over time, high blood sugar levels can lead to complications such as blindness, kidney failure, and heart disease. Diet, exercise, or medications can prevent people who are at high risk for type 2 diabetes from developing the disease. The standard way of identifying people at risk for type 2 diabetes is to measure blood sugar levels 2 hours after a standard amount of sugar is consumed. This test is called an oral glucose tolerance test, and it is inconvenient and costly. Easier and less costly ways of identifying people who might benefit from strategies to prevent diabetes would be useful.