A fasting plasma glucose test is used to diagnose prediabetes or diabetes. It is taken after the patient has gone at least 8 hours without eating. Then the blood sugar levels are tested. This test is repeated for another time for confirmation. Urine may also be tested. It is important to have a wellness checkup for early detection. Always consult your doctor about your health concerns. Consult your health professional about any changes you are thinking about making to your diet or lifestyle.
More technical information from the National Institute of Diabetes and Digestive and Kidney Diseases can be viewed here.