When you eat, whether the food is sweet or not, your body breaks some of the nutrients down into a sugar known as glucose. Cells need glucose for energy, but if you already have enough, the remaining glucose is left floating in the blood. The level of sugar that builds up in the bloodstream can be measured with an A1C test, also known as a glycated hemoglobin test. Levels between 5.7% and 6.4% signify pre-diabetes and an increased risk of diabetes. Levels above 6.5% indicate diabetes.