Medically Reviewed By: Tom Iarocci, MD
For someone with diabetes, a big part of taking care of yourself is making sure that your blood glucose levels are in a good range when you do your home testing. That said, every case of diabetes is unique, so while there are general guidelines about what is considered normal and abnormal, the exact figures that you should aim for, or your targets or goals, may vary and should be discussed with your doctor. If you are pregnant, your numbers will likely change, and it will be even more important to talk about your goals with your doctor and to stick to them.
Guidelines on Understanding Normal Range of Blood Glucose:
Normal blood glucose ranges are essentially facts of human biology that do not change; normal is normal and abnormal is abnormal, no matter what type of diabetes you have. Goal or target sugar levels are those that you are striving for, and those values can, indeed, differ or change depending on whether you have type 1 or type 2, your individual medications, and your individual response to those medications. There have been national recommendations for target levels, as well as international ones issued by the International Diabetes Federation (IDF).
The figures below are meant to be for guidance only. You and your doctor should be in agreement on your individual targets and at what point you may be in or out of range. As such:
1. The normal range if you have been fasting, no food or drink for 8 or more hours, is under 100 mg/dL. For nonpregnant people with diabetes, the American Diabetes Association (ADA) generally recommends that before a meal, blood glucose be 80–130 mg/dL.
2. After meals, the ADA recommends that 1-2 hours after the beginning of the meal (postprandial plasma glucose), plasma glucose be less than 180 mg/dl.
Diagnosing Diabetes with Plasma Glucose Test:
Many different tests are in use to check blood glucose levels, and each has its own strengths and weaknesses. In many cases, a single test is not used to make a diagnosis of diabetes or prediabetes, but there are some exceptions.
1. In the random plasma glucose test, the normal range is below 200 mg/dL. Blood glucose of greater than or equal to 200 mg/dl is indicative of diabetes.
2. In the fasting plasma glucose test, the normal range is below 100 mg/dL. A prediabetic range is between 100 mg/dL and 125 mg/dL. Anything above that is indicative of diabetes.
3. The Oral Glucose Tolerance Test (OGTT) is a test that checks your blood glucose levels before after you drink a special sweet drink. The “after” test is taken at the 2-hour time point after the sweet drink. It tells the doctor how your body processes glucose. Diabetes is diagnosed at 2-hour blood glucose of greater than or equal to 200 mg/dl. 140 mg/dl to 199 mg/dl is indicative of prediabetes; less than 140 mg/dl is considered normal.
Different Tests Have Different Rules:
- Random plasma tests can be taken at any time and don't require planning.
- The fasting test, by contrast, can only be taken if a patient did not eat or drink for at least eight hours. This is why it is generally completed first thing in the morning.
- The A1C is a test that averages out what your blood glucose levels have been over the last two to three months. One of the strengths of this test is that it does not require a glucose challenge (sweet drink), nor does it require fasting, so it can be done in your doctor’s office and sent to the lab on the spot.
With the A1C test:
1. The normal range is lower than 5.7%.
2. The prediabetes range is between 5.7% to 6.4%.
3. The diabetic range is anything 6.5% or higher.
Many people with diabetes have a goal A1C of less than 7%, but goals below and above this point are also possible.