Blood Glucose Tests

Overview & Description

Blood glucose, also called blood sugar, is the amount of glucose circulating in the blood. Glucose is a type of sugar. The body forms glucose when it breaks foods that a person eats down into a useable form of energy. Glucose is a main energy source for the body.

Measuring the amount of blood glucose in the blood helps evaluate:

• how the body is converting and breaking foods down into energy
  
• how the liver is working
  
• how the organs in the body that help regulate blood glucose are working
  

Blood glucose can be measured in a number of ways. Some of the tests that can measure blood glucose include:

• fasting blood glucose test
  
• glycosylated hemoglobin, also called HbA1c or hemoglobin A1c test
  
• oral Glucose tolerance test
  
• random blood glucose test
  
• self-monitoring of blood glucose, also called SMBG, or home blood glucose monitoring tests
  

Who is a candidate for the test?

A doctor may order a blood glucose test to evaluate the amount of glucose in the blood when he or she suspects a person has diabetes. These tests may also be done to rule out other causes of high or low blood glucose.
How is the test performed?

Here's how some of the tests may be done to check blood glucose levels:

• A fasting blood glucose test is the preferred method to diagnose Diabetes and rule out other conditions. This test is done after a person has had nothing to eat or drink except water for at least 8 hours. This is often called fasting. It is generally started overnight so the test can be done in the morning. Normal fasting plasma glucose levels are less than 110 mg/dL (milligrams per deciliter). Fasting plasma glucose levels of more than 126 mg/dL on two or more tests done on different days usually indicate diabetes. Levels between 110 and 126 indicate a condition known as Pre-Diabetes.
  
• An HbA1c, also known as glycosylated hemoglobin, measures the average blood glucose over the past 3 months. It is a good measure of long-term blood glucose control. This test is generally done only in people who have . It is used to assess how well their therapy is working.