Such testing can be done in a variety of ways, including the following:
The A1C test gives information about your average blood sugar levels over the past two to three months. It can be conducted at your doctor’s office at any time of day and without fasting (not eating or drinking anything except water).
This test is also sometimes called the hemoglobin A1C since it measures how glucose attaches to hemoglobin. These are red blood cells that live for about three months, so they can give your doctor a good estimate of your blood sugar levels over this period.
If the reading is below 5.7 percent, that’s considered normal. If your reading is 5.7-6.4 percent, you’ll be considered pre-diabetic. This condition means that your blood sugar levels are elevated but not to the point of being classified as diabetic, although it may progress to this point in the future. You’re diagnosed as having diabetes if your A1C level is at or above 6.5 percent.
2. Fasting Plasma Glucose (FPG)
The FPG test checks your fasting blood glucose levels, so you can’t have anything to eat or drink (except water) for eight hours before you have the test. It’s usually done in the morning.
- A normal reading is less than 100 mg/dL. You’re considered to be pre-diabetic if your reading is 100-125. If your reading is 126 or higher, you have diabetes.
3. Oral Glucose Tolerance Test (OGTT)
This is often used to test for gestational diabetes, a form of the disease that’s first diagnosed when you’re pregnant. The test is administered once before you drink a special glucose drink and again two hours afterward. The OGTT tells your doctor how your body processes glucose.
Under normal circumstances, your blood glucose level will rise after the drink. This will make your pancreas release insulin into your blood, which allows the glucose to be taken up by the cells. Your blood sugar level will then decrease. But if you don’t produce enough insulin or if your body doesn’t use it properly, your blood sugar levels will remain high.
- A normal reading is less than 140 mg/dL. You’ll be diagnosed as pre-diabetic with a reading of 140-199. With 200 or higher, your doctor will make a diagnosis of diabetes.
4. Random (also called casual) plasma glucose test
This blood sugar check can be conducted any time of day without fasting. It’s usually done if you’re having severe symptoms and your doctor doesn’t want to wait for a fasting test.
- If your level is at 200mg/dL or higher, diabetes is suspected, but your doctor will probably confirm the results with additional testing.
5. Home blood glucose test
You administer this test yourself at home if you have diabetes.
In general, your blood sugar levels should be about 70-130 mg/dL before meals and less than 180 one to two hours after the start of a meal. Over time, you’ll be able to learn how your blood sugar level reacts to foods, exercise and medication.
Blood glucose tests, whether administered at home or in a health-care setting, help your doctor determine if your blood sugar levels are normal or in the pre-diabetic or diabetic range. Depending on the results, he or she may repeat the test or order a different type to further verify the results.
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