Fasting Blood Sugar (FBS)
Also known as: FBS, Fasting Glucose, Blood Sugar Test
Measures blood glucose after an overnight fast and is a basic screening test for diabetes.
Why it's done
- Screen for diabetes
- Monitor diabetes
What it measures
Blood glucose level after fasting.
Preparation
Fast for 8-10 hours; water is allowed.
Normal range
Normal below 100 mg/dL; prediabetes 100-125 mg/dL; diabetes 126 mg/dL or more on two tests
Understanding results
Higher values suggest prediabetes or diabetes; confirm with HbA1c.
Related conditions
Ordered by
Frequently asked questions
Why is the Fasting Blood Sugar (FBS) test done?
Screen for diabetes, Monitor diabetes
How do I prepare for Fasting Blood Sugar (FBS)?
Fast for 8-10 hours; water is allowed.
What is the normal range for Fasting Blood Sugar (FBS)?
Normal below 100 mg/dL; prediabetes 100-125 mg/dL; diabetes 126 mg/dL or more on two tests
Medically reviewed by
Medical review pending
Last updated
9 October 2026
Sources
- ICMR standard treatment workflows
- Reference ranges vary by laboratory - always read your report with your doctor
This information is for general awareness and does not replace advice from a qualified doctor. Do not start, stop or change any medicine without medical advice.