The importance of testing and recording your blood sugar

Knowing your blood sugar (also called blood glucose) numbers is important to managing your diabetes. Keeping track of your blood sugar helps you see how food, physical activity, and medicine affect your blood sugar.

Using a blood glucose meter

Checking blood sugar is important for people with diabetes. A device called a blood glucose meter or glucometer can give you the information you need. These devices measure the sugar in the drop of blood you provide. Learn more about how to check your blood sugar at

Download and print a blood sugar diary

Blood sugar throughout the day

There are different times for testing blood sugar:

  • Fasting blood sugar—blood sugar after not eating for at least 8 hours (usually overnight)
  • Preprandial blood sugar—blood sugar prior to eating
  • Postprandial blood sugar—blood sugar 1 to 2 hours after the beginning of a meal

The readings from your blood sugar meter can help you understand your insulin needs for these different times of the day. The chart below shows the expected range of blood sugar in most non-pregnant adults. Individual blood sugar goals may vary. You should talk to your health care provider about your goals.

Preprandial blood sugar 80 to 130 (mg/dL)
Postprandial blood sugar Less than 180 (mg/dL)

In addition to fasting blood sugar checks, people with diabetes often test blood sugar before and after meals. They may also check at bedtime. To know more about how often to check your blood sugar, consult with your health care provider.

When to check your blood sugar

Many people starting on long-acting insulin may check their blood sugar up to several times a day, such as when they wake up and after each meal.

  1. When you wake up, log your “fasting” blood sugar. This is usually done in the morning before you eat anything. It is best to check when you haven’t had anything to eat or drink besides water for at least 8 hours (since food affects your blood sugar).
  2. After you eat,  log your “postprandial” blood sugar. This test is usually taken 1 to 2 hours after you eat. It measures how much your blood sugar level has risen due to the food you ate.

Inside the Novo Nordisk Blood Sugar Diary, you’ll find a list of suggested testing times. Be sure to follow your health care provider’s instructions on when and how often you should check your blood sugar.

The Blood Sugar Diary also includes space to note events that may have affected your blood sugar that day, like a larger meal or exercise.

The A1C test

An A1C test is a blood sugar test that helps you and your health care provider understand how well your treatment plan is working over time. For this test, your health care provider will ask you to provide a small blood sample, which will be tested in a lab or your health care provider's office. The results from the A1C test will show your average blood sugar over the last 3 months.

For many people with diabetes, an A1C of less than 7% is a good goal. If your result is 7% or more, you should talk to your health care provider. If you and your health care provider agree that your blood sugar is not well-controlled, you may need to change your treatment plan. Each person with diabetes has unique needs and goals. You should talk with your health care provider about how to lower your A1C level.


Blood sugar tracking tools and tips to support your daily progress

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