Blood Glucose

2-hour Postprandial Blood Sugar Test, Fasting Blood Sugar Test, Random Blood Sugar Test

How To Prepare

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 taking your morning dose of insulin or diabetes medication.

2-hour post-prandial blood sugar

For a 2-hour post-prandial test, eat a meal exactly 2 hours before the blood sample is taken. A home blood sugar test is the most common way to check 2-hour post-prandial blood sugar levels.

Random blood sugar (RBS)

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

Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may indicate. To help you understand the importance of this test, fill out the medical test information formClick here to view a form.(What is a PDF document?).


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Author: Caroline Rea, RN, BS, MSLast Updated: September 14, 2007
Medical Review: Caroline S. Rhoads, MD - Internal Medicine
Alan C. Dalkin, MD - Endocrinology
Andrew Swan, MD, CCFP, FCFP - Family Medicine

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Topic Contents
 Test Overview
 Why It Is Done
Arrow PointerHow To Prepare
 How It Is Done
 How It Feels
 Risks
 Results
 What Affects the Test
 What To Think About
 References
 Credits