Fasting Blood Sugar (FBS) - a blood test used to determine the amount of glucose in the blood. After a 12 hour fast, a range of 3.9 to under 6.1 mmol/l (70.2 to 100 mg/dl) is normal, while a level of 6.1 to under 7 mmol/l (100 to 126 mg/dl) is considered a sign of prediabetes.
Hemglobin A1C (HbA1c) - it is reported that higher levels of HbA1c are found in people with persistently elevated blood sugar. The normal range is below 5.7%. Levels between this and 6.4% is considered prediabetes, while 6.5% and higher confirms a diagnosis of diabetes.
Oral Glucose Tolerance Test (OGTT) - a standard dose of glucose is ingested by mouth and blood levels are checked two hours later. The 2 hour OGTT glucose level should be below 7.8 mmol/l (140 mg/dl). Levels between this and 11.1 mmol/l (200 mg/dl) means impaired glucose tolerance. Glucose levels above 11.1 mmol/l (200 mg/dl) is diagnosed as diabetes.