Medically Reviewed By: Tom Iarocci, MD
Glucose is the name for the sugar that circulates in your bloodstream and is used by the body’s cells for energy. To find out if your blood glucose levels are normal, your blood is tested and your results are compared with the known reference ranges. A variety of different tests are in use. For instance, fasting blood glucose levels can be taken first thing in the morning before you eat or drink anything. Another test, the A1C, is used to reflect what blood glucose levels have been averaging over the past two to three months.
What Your Results Mean:
Your doctor will likely be the first to see the results of your blood glucose test, and he or she will go over it with you. Some people with diabetes do home testing, which can give you a head start in terms of what the results mean. If you are pregnant, doctors will commonly use the 50-g oral glucose challenge test to screen you for gestational diabetes. You may be screened at 24 weeks, or perhaps earlier if you have certain risk factors. What your results mean can depend on your individual medical history, but general ranges for what is considered normal serve as good guides initially.
What Is Normal?
If you are a healthy adult, then your level should be close to normal at all times, but what is normal depends on how recently you have eaten. When you have been fasting for 8 hours, such as overnight, your levels should be less than 100 mg/dL. Regardless of whether or not you have diabetes, this number naturally climbs after a meal, and may stay elevated for approximately 2 to 4 hours, at which point the reading may get as high as 140 mg/dL in healthy adults; if you have diabetes, however, it may go higher, and the goal for tight control is generally to keep it below 180 mg/dL two hours after the meal.
Some Common Goals:
Glucose charts like the ones below tell you about some common goals for people with type 2 diabetes. No two people with type 2 diabetes are alike, and goals may differ depending on factors like your age, medical history, and how long you have had diabetes.
The following chart was adapted from the goal ranges as published by the Joslin Diabetes Center, and it outlines possible blood glucose ranges for a person who does and does not have diabetes. This should be used as a guide only, and it focuses on nonpregnant adults with type 2 diabetes.
Blood Glucose Levels Chart:
|Time of Check||Goal plasma blood glucose ranges
for people without diabetes
|Goal plasma blood glucose ranges
for people with diabetes
|Before breakfast (fasting)||< 100||70 – 130|
|Before lunch, supper and snack||< 110||70 – 130|
|Two hours after meals||
|A1C (also called glycosylated hemoglobin A1c, HbA1c or glycohemoglobin A1c)||< 6%||
< = less than
> = greater than
> = greater than or equal to
< = less than or equal to
Credit: The Chart above was obtained from Joslin Diabetes Center’s Guidelines for Pharmacological Management of Type 2 Diabetes.
Sources adapted from other organizations, such as the American Diabetes Association, may occasionally differ very slightly in the precise goals mentioned, but they are all in the same general ballpark. Historically, home meters measured glucose in whole blood; today, however, these machines calibrate results such that they are reported as mg/dL plasma glucose—the same as if you had blood drawn at the doctor’s office. Again, these are general ranges and your individual goals may differ from those shown here, so talk to your doctor.
Target Blood Sugar Levels For Adults With Diabetes Chart: