Glucose, Fasting (FBS)

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Rs.50
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Sample Type
  • Blood
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Test Code
#BB032
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Fasting
Yes
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Report within
24 Hours

The Glucose, Fasting (FBS) test measures your blood sugar level after an overnight fast, usually 8–12 hours. It is one of the most reliable and commonly used tests for diagnosing diabetes and prediabetes, monitoring blood sugar control, and assessing metabolic health. This is because fasting removes the effect of recent meals, hence the test gives a clear picture of how your body manages glucose at baseline.

At Torrent Diagnostics, we use global-standard laboratory technology to deliver precise results for early diagnosis and effective treatment planning.

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Why is the FBS Test Done?

Doctors recommend the fasting blood sugar test to evaluate how well your body regulates glucose and to detect early signs of diabetes.

Common medical reasons include:

  • Screening for diabetes
  • Detecting prediabetes
  • Monitoring glucose control in diabetic patients
  • Evaluating unexplained fatigue or excessive thirst
  • Investigating frequent urination or blurred vision
  • Checking for metabolic syndrome
  • Assessing high-risk individuals
  • Monitoring response to diabetes medication

Clinical values of FBS testing

  • Identifies blood sugar imbalance early
  • Helps prevent long-term complications
  • Guides treatment changes
  • Useful in routine health check-ups
  • Essential for metabolic health assessment
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Who Should Get the Test?

This test is recommended for people with symptoms or risk factors of high or low blood sugar.

You may need the test if you experience:

  • Increased thirst or hunger
  • Frequent urination
  • Sudden weight loss
  • Blurry vision
  • Slow wound healing
  • Numbness or tingling
  • Fatigue or weakness
  • Headaches or irritability

High-risk groups in India include:

  • People with family history of diabetes
  • Individuals with obesity
  • Those with high blood pressure or high cholesterol
  • People with PCOS
  • Pregnant women (risk of gestational diabetes)
  • Individuals with sedentary lifestyle
  • People above 40 years
  • Patients with fatty liver disease
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How to Read the Results?

Fasting Glucose Reference Guide

Fasting Glucose Level Category Meaning
< 100 mg/dL Normal Healthy glucose control
100-125 mg/dL Prediabetes Early impaired glucose regulation
? 126 mg/dL Diabetes Needs confirmation with repeat testing

High fasting glucose may indicate:

  • Diabetes
  • Prediabetes
  • Metabolic syndrome
  • Thyroid disorders
  • Hormonal imbalance
  • Pancreatic issues
  • Side effects of medicines like steroids

Low fasting glucose may indicate:

  • Hypoglycemia
  • Excess diabetes medication
  • Hormonal imbalance
  • Prolonged fasting
  • Excessive alcohol consumption
  • Liver disorders
Doctors may recommend additional tests such as HbA1c, PPBS, OGTT, or insulin levels for a complete evaluation.
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What to Ask the Doctor?

Helpful questions include:

  • What does my fasting glucose level mean?
  • Do I need further confirmatory tests?
  • Do I need lifestyle modifications or medication?
  • How often should I monitor my blood sugar?
  • Am I at risk of developing diabetes?
  • Does my diet need changes?
  • How can I prevent long-term complications?
How our test process works!
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STEP 01
Identity Verified at Every Step
Verified identity at every step to eliminate sample mix-ups
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STEP 02
Sterile, Barcoded Collection
Sterile, barcoded collection to maintain sample integrity
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STEP 03
Expert-Led Sample Collection
Trained professionals ensuring safe, accurate, and comfortable collection

FAQs To Help You Know Better

What does the FBS test measure?
It measures blood sugar levels after 8-12 hours of fasting.
Is fasting mandatory?
Yes, fasting is mandatory, as it ensures accurate results. However, you can drink water during this time.
Can FBS diagnose diabetes?
Yes, if levels are ? 126 mg/dL, but a repeat test may be needed to get a proper diagnosis. Also, in some cases, your doctor may recommended additional tests like PBS and HbA1c to confirm the diagnosis.
Can stress raise fasting sugar?
Yes, stress hormones can increase blood glucose level.
Can FBS be high even if I feel normal?
Yes, many people with early diabetes have no symptoms.
Can FBS detect hypoglycemia?
Yes, it helps identify unusually low fasting sugar.
Can children also take this test?
Yes, especially if overweight or showing diabetes symptoms.
How often should I repeat the FBS test?
Once a year for healthy adults; more often for high-risk groups.
Can water be taken during fasting?
Yes, plain water is allowed.
Does diet affect fasting sugar?
Yes, high-carb eating patterns can increase levels over time.
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