How does the fpg test define diabetes and pre-diabetes?

99 vs 126. By definition, a fasting plasma glucose over 126 on two separate days is confirmed diabetes. A fasting plasma glucose over 99 is pre-diabetes.
Blood Glucose. The fasting (8-12 hours) plasma glucose test is defined as follows - under 100 non-diabetic, 100-126 pre-diabetes, and greater than 126 as diabetes. Some people are using the hgba1c as a diagnostic test, but current recommendations do not indicate that as appropriate at this time. Hgba1c is recommended for monitoring of diabetic management.