Sugar (Fasting, Blood), Plasma – S0013a
About the Test
The Fasting Blood Sugar (FBS) test measures the level of glucose (sugar) in your blood after fasting for 8–12 hours. It is one of the most common tests used to screen for and monitor diabetes, prediabetes, and overall glucose metabolism. The test helps evaluate how effectively your body regulates blood sugar levels.
Why is this Test Done?
Doctors may recommend this test to:
- Screen for diabetes or prediabetes
- Monitor blood sugar control in diabetic patients
- Evaluate symptoms like excessive thirst, fatigue, or frequent urination
- Assess metabolic health during routine health checkups
- Monitor glucose levels during pregnancy
Preparation
- Fasting for 8–12 hours is required before sample collection
- Only water is allowed during the fasting period
- Avoid tea, coffee, juice, or food before the test
- Inform your doctor about any medications being taken
Sample Required
Normal Reference Range
| Result |
Blood Sugar Level |
| Normal |
Less than 100 mg/dL |
| Prediabetes |
100 – 125 mg/dL |
| Diabetes |
126 mg/dL or higher |
Symptoms of High Blood Sugar
- Increased thirst
- Frequent urination
- Blurred vision
- Fatigue
- Unexplained weight loss
Factors That May Affect Results
- Recent food intake
- Stress or illness
- Certain medications
- Lack of sleep
- Physical inactivity
