According to the American Diabetes Association (ADA), about 25 million (or roughly 8 percent) of US adults have been diagnosed with diabetes. And many more may not even know they have it. Luckily, there are simple tests that can let patients know if they have diabetes or prediabetes. The ADA recommends those of all ages who are overweight or obese, and have at least one risk factor of diabetes be screened. Even without the presence of diabetes risk factors, the ADA recommends screening every three years after turning 45. Read on for full details on the risk factors of diabetes, and learn what to expect as you prepare for screening.