Diabetes Education

Blood Glucose Testing

Frequently asked questions about blood sugar monitoring

Q. What is blood glucose monitoring?

A. Your diabetes care team may use this term: Self Blood Glucose Monitoring (SBGM). SBGM means checking your own blood sugar or blood glucose levels. Diabetes patients prick their fingers and place a drop of blood onto a test strip. A test strip is inserted into a machine called a "glucose meter." The glucose meter will provide a result in a few seconds. With the results, you may make changes in your management of diabetes to keep your blood glucose levels as close to normal ranges as possible.

A glucose meter is used by persons with diabetes to check what the blood glucose level is at the moment. Glucose monitoring also checks if the blood glucose level is too high or too low, and how your blood sugar is affected by food, exercise, medications, illness or stress.

ADA Blood Glucose Target Recommendations*, **
American Diabetes Association Guidelines

Time Goal
Pre-meal 90-130 mg/dl
Post-meal (1 - 2 hours after) less than 180 mg/dl

Three (3) month average blood glucose: A1c Test Result: 7.0% or lower

* FOR SAFETY PURPOSES: Lower targets may be recommended for persons who have lower risk for low blood sugar (hypoglycemia). Higher targets may be recommended for persons who have frequent or unrecognized high blood sugar (hypoglycemia).
** The American Association of Clinical Endocrinologists (AACE) recommends fasting blood glucose levels below 110 mg/dl, 2 hour post meal values below 140 mg/dl and A1c levels less than 6.5%.

Q. A1c Question: Why is it necessary to check 3-month blood sugar level averages?

A. The A1c test is a medical test that is done routinely as a preventative measure to detect potential medical problems early, so complications can be avoided. This proactive testing helps slow or reverse damage before any organ impairment has affected a body function. The American Diabetes Association (ADA) recommends on average most persons with diabetes should have A1c levels tested four (4) times per year.

The A1c test shows average blood glucose levels over a 3-month period. The results reveal overall control. When your physician monitors overall control this result is helpful to show blood glucose averages. With daily blood glucose monitoring, single tests are performed to show the blood sugar level at the exact time of the testing. These results are helpful, but not the best way to check overall control.

It is important for your physician to know how your meal plan, exercise and medication work together to control your diabetes. A1c numbers of 8.0% or above generally reflect poorly controlled diabetes. A1c numbers can be changed or lowered only after weeks of good diabetes control, which includes careful attention to exercise, stress management, medication schedule, and healthy meal plan.

Q. When is frequent testing of blood glucose necessary?

A. During times of stress, illness, trauma/injury, or surgery frequent blood glucose monitoring is recommended.

More frequent blood glucose monitoring is recommended during exercise. Exercise causes insulin to work more effectively, and exercise uses up blood glucose, thus lowering blood glucose levels.

Persons with diabetes needs to refrain from exercise if there are ketones in the urine and the blood glucose level is 250 mg/dl or above. If there are no urine ketones, but the blood sugar levels are 300 mg/dl or above, then exercise should be avoided until blood glucose levels are within the target range.

Q. What can I do to avoid low blood glucose during exercise?

A. Here are some ways to avoid low blood glucose while exercising:

  • Before beginning exercise: Check blood glucose level. Eat one carbohydrate serving (15 grams carbohydrate) before becoming active if blood glucose is below 100 mg/dl. Examples: 1 slice of bread, ⅓ cup cooked pasta or rice, 1 cup fresh fruit, or 1 8-ounce glass of milk.
  • See how your medications and food choices are working. Check blood glucose levels to be sure.
  • After 3 hours of intense activity, test blood glucose levels for within one (1) hour after exercise begins.
  • When exercise lasts for more than one (1) hour, you may experience possible delayed hypoglycemia.

More information about Diabetes & Exercise.

Q. How do I record blood glucose results?

A. Write down the following information for each blood glucose level test:

  • Date and Time
  • Blood Glucose Meter reading
  • Comments on any concern that may affect the reading(s):
    • Example: Sickness, Stress, Large meal, or more than normal amount of physical activity.

Blood Glucose Meter Log Books generally have a self-assessment page. Complete with your physician the sections on individual goals for individual targets.

Q. What are the benefits of recording the results of my blood glucose tests?

A. Your log will help you communicate your blood glucose results to the health care team. Take your blood glucose log book to all physician and health care team visits. You can review problems that are occurring at certain times of the day with high or low blood sugar levels with your health care professional. Changes in treatment plans can be made if necessary. By monitoring your blood glucose levels regularly, you will be able to see how different lifestyle factors such as food, exercise, illness, and stress affect your numbers.

Write the blood glucose results in a notebook or glucose meter logbook each time you test. If any changes are necessary in meal plan, nutritional intake, medication or activity plan, your health care team members can effectively evaluate this from your recorded results. Your health care team member will assist you with understanding the blood glucose results, and individualize your care plan.

Also, it is important to remember that you will feel your best when you keep your blood glucose within the recommended target range(s). With well managed blood glucose levels, improvements in blood pressure and cholesterol levels generally result. This allows you to greatly lowering your risk for diabetes complications such as vision problems, kidney disease, heart disease and nerve damage.

Jeanna Rhoulhac, RD, LD/N, CDE, has been dedicated to helping people with diabetes for almost 20 years. Jeanna’s interest in diabetes began at an early age as her maternal grandmother had type 2 diabetes. Providing her clients with an individualized plan of care is very important to Jeanna, who strives to motivate and support her clients in every way. More about Jeanna

The goal of Destination Diabetes® is to be a useful and credible resource for the more than 20 million children and adults who have diabetes in the U.S. and their families. Destination Diabetes® provides information on a wide range of diabetes health and wellness topics. Articles are written or reviewed by diabetes advisors who have experience in diabetes education.