Why do most diabetics worry about the morning fasting blood sugar being high?-Written by Dr. Harold Gunatillake FRCS, MBBS, AM (Sing), FICS (US) FIACS (US) Fasting blood sugar is a test done on your early morning wake up time check, or when you visit the collecting centres to give blood for biochemical screening, fasting for 12 hours. Fasting blood sugar is more diagnostic to check whether you have excess blood sugar. That would be the routine test your doctor will request on your annual blood check, sometimes with the HbA1C test If it is on the high side your doctor refers you for a random plasma glucose test or oral glucose tolerance test. The oral glucose tolerance test is the gold standard for diagnosing type 2 diabetes. If your fasting level is higher than 126 mg/L (7 mmol/L) you have diabetes. So, lets go back to the fasting blood sugar ...