According to the American Diabetes Association, the A1C test is the best diagnostic test to monitor how your blood glucose is reacting to treatment or other lifestyle changes you’ve made because it isn’t skewed by daily changes to your eating. However, that doesn’t mean you should use it exclusively. The other types of tests monitor your day-to-day glucose levels and can provide valuable information about how your daily habits affect your health.
Fasting Plasma Glucose Test (FGT)
Doctors will often use other tests, like fasting plasma glucose in combination with A1C in order to ensure accuracy. If you have a fasting plasma glucose of 126 mg/dL or above, the exam indicates that you have diabetes. The test indicates you have prediabetes if your fasting blood glucose is between 100 mg/dl and 125 mg/dL. Any fasting plasma glucose below 100 mg/dL is considered to be normal. These tests typically occur in the morning after the body has fasted for at least 8 hours.
Oral Glucose Tolerance Test (OGTT)
The OGTT is used to determine how successful your body is at processing sugars in your food. Doctors classify oral glucose tolerance scores of 200 mg/dL or above as diabetes. They use scores of 140 mg/dL to 199 mg/dL to diagnose prediabetes. An oral glucose tolerance that is below 139 mg/dL is considered normal. The A1C test isn’t often used to check for diabetes in pregnancy, instead, this test is used.
Random Blood Glucose
This test measures how much glucose is in your blood. To run the test, doctors will draw blood and there’s no need to fast in preparation. When a patient has a blood glucose level greater than 200 mg/dL and is experiencing symptoms of diabetes, the doctor can diagnose you with diabetes. When you don’t have diabetes symptoms, the doctor will use one of the other tests to verify accuracy. A normal score on this test is below 125 mg/dL; however, scores vary greatly depending on the time of day and how recently you’ve eaten.
Continuous Glucose Monitor (GCM)
If you’ve had hypoglycemia repeatedly, over time, your body doesn’t show symptoms that lead you to take action, which is extremely dangerous. You may want to have a continuous glucose monitor, which uses a tiny wire under your skin to constantly check your blood glucose level. It sends your glucose levels to a receiver so you can monitor when your blood sugar is too high and when it’s too low and behave accordingly.