FBS (Fasting Blood Sugar) Test For Blood Glucose Levels

FBS (Fasting Blood Sugar) Test For Blood Glucose Levels

FBS (Fasting blood sugar) Test is a simple, common blood test to screen for diabetes, prediabetes or gestational diabetes (during pregnancy). It’s also called a fasting blood glucose test.


FBS Test 

Here are the basic details for FBS Test.

Also Known As Fasting Blood Sugar Test, Fasting plasma glucose (FPG) test
Type Blood Test
Measure glucose (sugar) levels in blood
Sample Type Blood
Preparation No Special Preparation Required
Fasting Yes
Gender All
Age-Group 18+
Normal Value 70-100 mg/dL
Reporting Time 1 - 2 hours
Cost 50 - 200* INR

*FBS Test Price range may vary as per location, lab type, and procedure of lab test.


FBS Test Full Form

The full form of the FBS Test is a Fasting Blood Sugar Test.


FBS Test Means

FBS Test is used to measure the level of glucose (sugar) in the bloodstream after a period of fasting.

  • The FBS test is often done as part of a routine health check or to evaluate symptoms such as frequent urination, thirst, and blurred vision.
  • To prepare for the test, you will need to fast for at least 8 hours before the blood sample is taken.
  • The test involves drawing a blood sample, typically from a vein in the arm.
  • Normal FBS levels are usually between 70-100 mg/dL
  • If fasting blood glucose is  100 - 125 mg/dL indicates changes in lifestyle and monitoring glycemia.
  • If fasting blood glucose is 126 mg/dL or higher indicates diabetes.
  • If fasting blood glucose is below 70 mg/dL indicates Hypoglycemia which results in experience dizziness, sweating, palpitations, blurred vision, and other symptoms.
  • FBS test results can be affected by a variety of factors, including stress, medications, and other health conditions.
  • Your healthcare provider will interpret the FBS test results and determine if further testing or treatment is necessary.
  • If you are diagnosed with diabetes, you may need to monitor your blood sugar levels regularly and make lifestyle changes such as diet and exercise to manage the condition.
  • It is important to follow all pre-test instructions provided by your healthcare provider to ensure accurate and safe testing.

Interesting Facts About Fasting Blood Sugar

  • Fasting blood sugar (FBS) is a measure of the glucose level in the bloodstream after fasting for a specific period, typically 8 hours or overnight.
  • FBS is commonly used to screen and diagnose diabetes and prediabetes, as it reflects the body's ability to regulate blood sugar levels in a fasting state.


FBS Test Purpose

Here are some purposes of the FBS (Fasting Blood Sugar) test:

  • To diagnose diabetes mellitus
  • To monitor blood sugar levels in diabetic patients
  • To assess the risk of developing diabetes or other metabolic disorders
  • To evaluate the effectiveness of diabetes medications or lifestyle changes
  • To detect conditions that affect blood sugar levels, such as pancreatic disorders or hormonal imbalances.


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FBS Test Preparation

Here are some preparation tips for FBS (Fasting Blood Sugar) test:


Before Test

  • Fast for at least 8 hours prior to the test
  • Drink plenty of water to stay hydrated
  • Avoid alcohol and strenuous exercise the day before the test
  • Inform your doctor of any medications you are taking


During Test

  • A healthcare professional will draw a blood sample from your arm
  • The process usually takes a few minutes and causes minimal discomfort


After Test

  • Resume normal activities and diet as instructed by your doctor
  • If you experience any symptoms such as dizziness, lightheadedness, or fainting after the test, inform your doctor immediately
  • Wait for the test results to discuss with your doctor for further evaluation or treatment.


For FBS Test Prepare by staying hydrated all over day, and inform your doctor of medications before a fasting blood sugar test.


FBS Test Procedure

Here are the steps involved in the FBS (Fasting Blood Sugar) test procedure:

  • The healthcare professional will ask you to fast for at least 8 hours prior to the test.
  • Upon arrival, the healthcare professional will collect a blood sample from your arm using a sterile needle.
  • The collected blood sample will be sent to a laboratory for analysis.
  • In the laboratory, the blood sample will be analyzed to determine the glucose concentration in your blood.
  • The test results will be reported to your doctor, who will discuss them with you along with any necessary follow-up or treatment plans.


FBS Test Result

Here are some points for interpreting FBS (Fasting Blood Sugar) test results, excluding the normal range:

  • FBS levels above 100 mg/dL indicate hyperglycemia or high blood sugar, which may be a sign of diabetes or prediabetes.
  • FBS levels below 70 mg/dL indicate hypoglycemia or low blood sugar, which can be caused by certain medications or conditions such as liver disease, kidney failure, or pancreatic disorders.
  • It's important to consider other factors such as symptoms, medical history, and additional tests when interpreting FBS results.
  • FBS test results may vary depending on the laboratory or healthcare provider, and it's recommended to consult with a doctor for proper interpretation and diagnosis.


FBS Test Report

FBS Test Report - Drlogy Test

FBS Test Report PDF


FBS Test Normal Range

Here is the normal range of FBS (Fasting Blood Sugar) test results in a table format:

Gender Fasting Blood Sugar Interpretation
Unisex Less than 70 mg/dL or 3.9 mmol/L Low blood sugar (hypoglycemia)
Unisex 70 - 100 mg/dL or 3.9 - 5.6 mmol/L mmol/L Normal range
Unisex 100-125 mg/dL or 5.6  - 6.9 mmol/L mmol/L Prediabetes
Unisex 126 mg/dL or 7.0 mmol/L or higher Diabetes

Note that these ranges may vary slightly depending on the laboratory or healthcare provider. It's important to consult with your doctor for interpretation of your specific FBS test results.


FBS Test Interpretation

Here's an example of FBS (Fasting Blood Sugar) test interpretation.

FBS Test Result Interpretation
Less than 70 mg/dL Hypoglycemia or low blood sugar
70-99 mg/dL The normal fasting glucose level
100-125 mg/dL Impaired fasting glucose level, indicating prediabetes
126 mg/dL or higher Hyperglycemia or high blood sugar, indicating diabetes


It's important to note that these ranges may vary depending on the laboratory or healthcare provider, and interpretation should be done in consultation with a doctor.


FBS Test High

Here are some possible FBS (Fasting Blood Sugar) test high causes.

High FBS Test Causes Explanation
Diabetes Mellitus A chronic disease that affects how your body processes glucose (sugar).
Pancreatitis Inflammation of the pancreas can interfere with insulin production, leading to high blood sugar levels.
Cushing's Syndrome A hormonal disorder occurs when your body is exposed to high levels of the hormone cortisol for an extended period. This can lead to insulin resistance and high blood sugar levels.
Hyperthyroidism An overactive thyroid gland can lead to an increase in blood sugar levels.
Steroid Medication Long-term use of steroid medication can cause insulin resistance and high blood sugar levels.
Stress When you're stressed, your body releases hormones that can cause an increase in blood sugar levels.
Obesity Excess weight can lead to insulin resistance, which can cause high blood sugar levels.
Sedentary Lifestyle Lack of physical activity can lead to insulin resistance and high blood sugar levels.


FBS Test Low

Here are some possible FBS (Fasting Blood Sugar) test low causes.

Possible Causes of Low FBS Test Results Description
Hypoglycemia (low blood sugar) This can occur due to excessive physical activity, insufficient food intake, or certain medical conditions such as adrenal insufficiency or insulinoma.
Excessive insulin dosing Taking too much insulin medication than required can lower blood sugar levels.
Alcoholism or excessive alcohol consumption Alcohol can interfere with the liver's glucose production resulting in low blood sugar levels.
Malabsorption or malnutrition Certain gastrointestinal diseases or poor nutrition can cause malabsorption of glucose leading to low blood sugar levels.
Liver disease The liver is responsible for glucose production and storage, liver diseases such as cirrhosis can lead to reduced glucose production resulting in low blood sugar levels.
Pancreatic tumors Certain tumors in the pancreas can secrete excess insulin, resulting in low blood sugar levels.
Certain medications Some medications like sulfonylureas, used to treat type 2 diabetes, can lower blood sugar levels as a side effect. Other medications like beta blockers can mask symptoms of low blood sugar.

It's important to note that these possible causes may vary depending on the individual and interpretation should be done in consultation with a doctor.


High FBS test results may indicate possible diabetes, while low results could suggest hypoglycemia or other conditions.


Specimen Requirments For FBS Test

Here are the specimen requirements for the FBS Test.

Specimen Blood Serum
Volume 1 ml
Container Red-top tube or gel-barrier tube.


FBS Test is Safe?

The FBS test is generally considered safe, and there are few risks associated with the procedure.

  • The test involves taking a blood sample, which may cause some discomfort, bruising, or bleeding at the puncture site. However, these side effects are usually minor and resolve quickly.
  • It is important to follow all pre-test instructions provided by your healthcare provider to ensure accurate and safe testing. If you have any concerns about the test, you should discuss them with your healthcare provider.


When Do You Get FBS Test Results?

  • The FBS test results are usually available within 1 -2 hours to a day.
  • However, the exact time frame may vary depending on the testing facility and the method used to analyze the blood sample.


FBS Test Limitation

Here are some possible limitations of the FBS Test.

  • Limited diagnostic value for diabetes diagnosis alone.
  • FBS levels can vary due to various factors, such as stress, illness, and medications.
  • FBS test does not provide information on postprandial (after-meal) blood sugar levels.
  • Fasting requirements may cause inconvenience for some individuals.
  • Additional tests may be needed for an accurate assessment of glucose metabolism.


FBS Test Risk Factors

Here is the potential risk factor of the FBS Test.

  • Diabetes or prediabetes diagnosis.
  • Obesity or overweight.
  • Sedentary lifestyle or lack of physical activity.
  • Family history of diabetes.


Doctor Recommendations After FBS Test Result

Here are Doctor recommendations or consult a specialist after FBS Test.

FBS Test Result Doctor to Visit Reason to Visit
High Endocrinologist Possible diabetes diagnosis
Normal General Physician Routine follow-up or check-up
Low General Physician Potential hypoglycemia or other conditions


FBS Test Price

Here are the estimated FBS Test Price in India with different top cities:

City Price Range (INR)*
Mumbai 50 - 200
New Delhi 100 - 200
Bangalore 100 - 200
Hyderabad 50 - 200
Kolkata 100 - 200
Pune 50 - 200
Lucknow 100 - 200
Noida 50 - 200
Surat 100 - 200
Gurugram 50 - 200
Patna 100 - 200
Chennai 50 - 200
Jaipur 100 - 200
Ahmedabad 50 - 200

*Prices are approximate and vary depending on a specific laboratory or healthcare facility.



Overall, FBS Test commonly used diagnostic tool to measure blood sugar levels and screen for diabetes and other related conditions. Also check Drlogy Test for detailed information about all medical tests for patients, doctors, scholers and medical students.



  • Blood Sugar Level - Wikipedia [1].
  • Blood Glucose Monitoring - StatPearls [2].



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What is an FBS Test?

  • FBS stands for Fasting Blood Sugar Test, which measures the glucose (sugar) levels in the blood after an overnight fasting period.
  • It is a common test used to diagnose and monitor diabetes mellitus and assess blood sugar control.

Why is an FBS Test done?

  • An FBS Test is done to evaluate blood sugar levels and screen for diabetes or prediabetes.
  • It is also used to monitor blood sugar control in individuals with diabetes and assess the effectiveness of diabetes management strategies.

How is an FBS Test performed?

The FBS Test requires fasting for at least 8 hours before the test. Only water is allowed during the fasting period.

  • A blood sample is taken from a vein, usually in the arm, and sent to a laboratory for analysis.
  • The blood sample is tested to measure the fasting blood sugar levels, and the results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L).

What do the results of an FBS Test mean?

Normal fasting blood sugar levels typically range between 70-99 mg/dL (3.9-5.5 mmol/L).

  • Elevated fasting blood sugar levels may indicate prediabetes (impaired glucose tolerance) or diabetes, depending on the severity of the elevation.
  • Abnormally low fasting blood sugar levels (hypoglycemia) may be a sign of an underlying health condition or medication side effect and require further evaluati

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