Fasting blood sugar provides vital clues about how the body is managing blood sugar levels. Blood sugar tends to peak about an hour after eating, and declines after that.
High fasting blood sugar levels point to insulin resistance or diabetes. Abnormally low fasting blood sugar could be due to diabetes medications. The results of a fasting test with respect to glucose levels in the body are as follows: Normal: 3.9 to 5.5 mmol/l (70 to 100 mg/dl) Prediabetes or Impaired Glucose Tolerance: 5.6 to 7.0 mmol/l (101 to 126 mg/dl) Diagnosis of diabetes: more than 7.0 mmol/l (126 mg/dl)
Normal fasting blood glucose — or blood sugar — is between 70 and 100 milligrams per deciliter or mg/dL for people who do not have diabetes. The standard diagnosis of diabetes is made when two separate blood tests show that your fasting blood glucose level is greater than or equal to 126 mg/dL. The fasting blood sugar test is also used to test the effectiveness of different medication or dietary changes in people already diagnosed as diabetic.
Blood glucose tests are either random or fasting tests. For a fasting blood glucose test, you can’t eat or drink anything but water for eight hours before your test. You may want to schedule a fasting glucose test first thing in the morning so you don’t have to fast during the day.
If you had a fasting blood glucose test: A level of 100 to 125 mg/dL (5.6 to 6.9 mmol/L) means you have impaired fasting glucose, a type of prediabetes. This increases your risk of developing type 2 diabetes. A level of 126 mg/dL (7 mmol/L) and higher usually means you have diabetes.