Blood Sugar Test
A fasting blood sugar test measures blood glucose levels. High levels indicate diabetes and insulin resistance, which requires treatment to control the blood sugar levels.
When is a fasting blood sugar test prescribed?
A doctor may advise this test
- To screen and diagnose prediabetes and diabetes.
- To detect diabetes during pregnancy or gestational diabetes
- To check the efficacy of treatment in patients already taking treatment for diabetes
- To monitor sugar levels in patients who are at high risk of diabetes.
What are the components of a fasting blood sugar test?
A few different protocols may be used to evaluate glucose levels-
- FASTING BLOOD GLUCOSE - Commonly called fasting blood sugar. This test measures the level after a fast of at-least 8 hours.
- RANDOM BLOOD GLUCOSE - Sometimes your blood glucose will be measured when you have not fasted.
- GLUCOSE TOLERANCE TEST - A glucose tolerance test measure glucose level after Fasting and after intake of liquid containing specific amount of glucose.
- GLUCOSE TEST FOR GESTATIONAL DIABETES - A specific protocol is used to help diagnose gestational diabetes, which diabetes that get developed during pregnancy.
Procedure and prerequisites
Do not eat or drink anything other than water for 8-12 hours before fasting blood glucose test. A blood sample is taken from the vein.
Reference range for fasting blood glucose
| Less than 100 mg/dL |
Normal |
| Between 110–125 mg/dL |
Prediabetes |
| Greater than 126 mg/dL |
Diabetes |
Sometimes two or more samples are taken to confirm diabetes.