Diabetes is detected when your health care provider or nurse finds a high level of sugar in your blood or urine. The best time to test your blood sugar level is after you have gone for 8 hours without eating or drinking. This is known as a fasting blood sugar. A range for a normal fasting blood sugar is between 3.3 and 5.5 mmol/l (60 and 99 mg/dL). Levels between 5.6 to 6.9 mmol/l (100 and 125 mg/dL) are considered pre-diabetic.