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Blood Glucose: About This Test

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What is it?

A blood glucose test measures the amount of a type of sugar, called glucose, in your blood. A few different types of blood glucose tests are used.

  • Fasting blood sugar (FBS) measures blood glucose after you have not eaten for at least 8 hours. It is often the first test done to check for prediabetes and diabetes.
  • Random blood sugar (RBS) measures blood glucose regardless of when you last ate.

Why is this test done?

Blood glucose tests are done to check for diabetes or to see how well treatment for diabetes is working.

How do you prepare for the test?

Fasting blood sugar (FBS)

For a fasting blood sugar test, do not eat or drink anything other than water for at least 8 hours before the blood sample is taken.

If you have diabetes, you may be asked to wait until you have had your blood tested before you take your morning dose of insulin or diabetes medicine.

Random blood sugar (RBS)

No special preparation is needed before having a random blood sugar test.

How is the test done?

A health professional uses a needle to take a blood sample, usually from an arm.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

Go to http://www.healthwise.net/patientEd

Enter G279 in the search box to learn more about "Blood Glucose: About This Test".

Current as of: April 30, 2024

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

Current as of: April 30, 2024

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.