fasting blood sugar level
Metabolic Health
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What is fasting blood sugar level?

Blood sugar fasting level, as the name implies, fasting involves going eight hours without eating or drinking anything save water. It is used as a diabetes test.

After a fast, blood glucose levels are measured as part of a test for the metabolism of carbohydrates.

What is a fasting blood sugar test? (fbs test)

Fbs test (fbs test) means measuring the blood glucose levels after at least of 8 hours of fasting. It is frequently the initial test used to check for prediabetes and diabetes.

To take the test, your finger is pricked with the pricker or a needle is used to collect a blood sample from the vein of your arm. After this, the test is done to get the fasting blood sugar level.

According to the sugar fasting test, below is the sugar level for people with diabetes, prediabetes, and normal people. Also know about pp blood sugar

  Result     Fasting Blood Sugar Test  
  Diabetes       126 mg/dL or above    
Prediabetes      100 – 125 mg/dL      
   Normal       99 mg/dL or below    

Thus from the table, we can conclude that a fasting blood sugar level of 126 mg/dL or higher means you have diabetes, 100 to 125 mg/dL means you have prediabetes, 99 mg/dL or normal.

What is the purpose of a fasting blood sugar test or fasting Diabetes test?

The sugar level after a fast is always high in the blood fbs test. After you eat, your blood glucose levels instantly increase and then gradually decrease. It occurs as a result of the fact that when you eat anything (carbs), they break down into simpler things like glucose (sugar). Your blood sugar levels rise as a result of those sugars entering the bloodstream. The release of insulin by your body causes the cells to begin absorbing sugar from your blood at the same moment.

A hormone called Glucagon is produced in response to fasting, which raises the body's glucose levels. If a person does not have diabetes, insulin will be produced by their body to balance their blood sugar levels. But, a diabetic individual won't make enough insulin or be able to use it efficiently. Blood glucose levels won't balance out as a result. As a result, a diabetic person's blood sugar levels will be higher than those of a non-diabetic person.

The blood sugar fasting test's goal is to determine how your body regulates its sugar levels. Between-meal blood sugar levels give a picture of how your body regulates the sugar levels. A person's body won't make or use insulin if they have type-1 or type-2 diabetes. Thus it is simpler to determine whether a person has diabetes or is at risk for developing it.

When to get a Fasting Blood Sugar Test?

You can opt for fasting for blood sugar test if you see the following symptoms:

  • The feeling of thirst increases.
  • Urination frequency increases
  • Feel hungry
  • Weight loss
  • Ketones in the urine
  • Fatigue
  • Irritability
  • Blurred vision
  • The healing process takes time.
  • Skin, vaginal, or any types of infections that occur frequently.

A person must go for the fasting sugar test, after 8-12 hours of not eating or drinking anything except water.

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How do I prepare for a fasting blood sugar test?

Do not eat or drink anything other than water for at least 8 hours before the blood sample is obtained for a fasting blood sugar test. If you have diabetes, you may be requested to delay taking your morning dosage of insulin or diabetes medication until your blood is tested.

What to expect on the day of fasting blood glucose test?

When you are getting your fasting sugar levels checked, it is natural that you would want to be prepared for the same. Your fasting blood glucose level will be tested with a common blood draw from the vein.

  • The lab technician will clean the area on the inner side of the elbow to disinfect and sterilize it so that any infection can be prevented.
  • They will then tie a band around the upper arm that will pump up the veins with blood and make them more prominent
  • Then, a new and clean needle will be inserted into the vein to draw some blood into a vial.
  • They will remove the band and the needle and will put some pressure on the site of insertion to restrict any bleeding. They may also seal the area with cotton and a band-aid.
  • They will write down your personal information on the vial so that the label will help them distinguish your sample from others’

Once this process is done, the technicians will send your blood sample for testing to the lab. They will let you know when the results will be provided based on the type of blood test.

Are there any risks with a fasting blood sugar test?

No, there might not be any risks to the fasting blood test. It is a simple test that is based on drawing blood from the vein with almost no chance of complications. Make sure that the area is clean before the insertion of the needle and that a new (packaged) needle is used to draw blood. In case you have a problem with easy scarring or continuous bleeding, put enough pressure on the site. If you notice any unusual redness or itching, visit your doctor.

When will I receive the fasting blood sugar test results?

You will receive the results of this test within hours. The glucose fasting normal range will also be mentioned on the report for you to check. However, visiting your doctor to get an accurate interpretation of the results would be a better idea. Before diagnosis, it would be best to get your blood tests done by a lab.

Fasting blood sugar levels chart

Fasting Blood Sugar Levels Conditions Diagnosed
99 mg/dL or lower Normal FBS Level
100-125 mg/dL Prediabetes
126 mg/dL or above Diabetes

What are the sugar Levels in Healthy Individuals after fasting?

Blood glucose levels, often known as blood sugar levels, can be normal, high, or low. Sugar levels are usually checked 8 hours after eating.

  • After 8 hours of fasting, a healthy adult (male or female) should have blood sugar levels between 70 and 100 mg/dL.
  • While a normal sugar level in a healthy person after 2 hours of eating is between 90 to 100 mg/dL.

How to maintain healthy fasting blood sugar levels?

It is important to maintain a healthy diet in order to keep blood sugar levels fasting from climbing too high. Strategies include:

  • Consuming a variety of fiber-rich meals.
  • Choose whole grain bread and spaghetti over white bread and pasta.
  • Consuming high-protein foods to boost feelings of fullness.
  • Minimizing sugar and salt consumption.
  • Consuming nonstarchy vegetables.

Different tests for Type 1 Diabetes, Type 2 Diabetes, and prediabetes

Diabetes is a complicated and nuanced condition. It is not limited to just one or two types. Owing to the very nature of the condition, the diagnosis is also multi-faceted. Several types of tests are conducted to ensure that accurate diagnosis is done so that the course of treatment and prognosis is correct. There are also some other types of diabetes tests like the A1C Test, Glucose Tolerance Test, Random Blood Sugar Test, Tests for Gestational Diabetes, Glucose Screening Test, Glucose Tolerance Test.

The sugar test fasting is accurate, but only at the moment. It limits the overall measurement of blood sugar control because the blood sugar depends on the time of the day, activities of the day, and hormonal change. Therefore, it is essential to do 1 or 2 tests to confirm diabetes since different tests follow different procedures and raise chances of a more accurate diagnosis. Read more about gdm treatment.

A1C Test

Glucose binds to haemoglobin in your blood cells. If the glucose in the body is more, then haemoglobin will have more glucose bound with it. The A1C test measures the amount of this bound glucose on haemoglobin and tells you about your average sugar level in the past three months. The blood sugar level is calculated in terms of percentages.

Procedure for the A1C Test

  1. The technician will draw blood from the vein of your upper arm with the help of a needle. Before drawing the blood, he will tie the elastic band above the vein to help push the blood down. 
  2. After drawing the blood, the cotton ball will be pressed over the area of the inserted needle to stop bleeding if any. Later, he will place a bandage over the area.
  3. The result will be determined in the office or lab of the technician. This is called a point-of-care test.

The blood sugar level for the A1C test is as below:

  Result           A1C Test      
  Diabetes      6.5% or higher    
Prediabetes between 5.7 and 6.4%
   Normal        below 5.7%      

Glucose Tolerance Test

Glucose Tolerance Test

A glucose tolerance test is done before and after drinking the sugary liquid. Before this test, you have to do overnight fasting. The technician will draw your blood and test it. After this, he will give you the liquid containing sugar and then do the blood sugar level test after 1 hour, 2 hours, and sometimes after 3 hours.

Procedure for the Glucose Tolerance Test

  • The technician tests the blood sample before starting the test.
  • It gives the person a sugary drink to consume, containing glucose and water. 
  • He will take the further blood samples after every 20-60 minutes for a total of 2 hours. 

The blood sugar level for the Glucose Tolerance Test is as follows:-

  Result     Glucose Tolerance Test
  Diabetes     200 mg/dL or above  
Prediabetes     140 – 199 mg/dL    
   Normal     140 mg/dL or below  

Fasting blood sugar tests

Fasting Blood Sugar Test

This is one of the first and most important tests conducted to diagnose diabetes. Those with type 1, type 2, and prediabetes need to conduct this test every 3 months at least at the lab. This level can also be tested at home after diagnosis with the glucometer use.

Glucometer test

Glucometer Test

People diagnosed with any kind of diabetes would have to conduct regular testing at home. In most cases, doctors will encourage their patients to purchase a glucometer using which their sugar levels can be tested at different times of the day. The overall treatment plan will depend on the sugar readings throughout the day.

Continuous glucose monitoring

For daily use, CGM can be a good option. This device gives a detailed and accurate picture of the sugar readings and it can get easy to determine and check for fluctuations throughout the day. This device can get expensive and may not be affordable for everyone. Medical technology has seen several advancements in recent times. Even regarding chronic illnesses, healthcare companies are constantly researching better and newer ways to make the lives of people living with diabetes and other conditions easier. Along with the insulin pump, one such invention that has significantly improved the quality of life of T1Ds and T2Ds is the continuous glucose monitoring machine (CGM).

If you have diabetes or are living with someone who is dealing with this condition, you would probably be aware of the number of times they would have to prick their fingers to check their blood glucose levels daily. Carrying your glucometer everywhere you go and pricking can get cumbersome. The CGM device is a sleek circular device that can be placed on your arm. It has a sensor that is inside the arm – this sensor measures and records the blood sugar levels every 15 minutes in real time.

You can keep this CGM machine inserted into your arm for 14 days and at the end of the duration, you can calibrate the device with a reader that comes with it. The reader will record your blood glucose levels and will provide you with a graph and numeric values of the readings.

If you are on the insulin pump (the higher versions), you can also calibrate and link your CGM to the pump. This will act as an ‘automatic pancreas’ as any high or low sugar readings will make the pump stop the basal dose of insulin or inject more to lower the level. The CGM is one of the most effective devices for people living with diabetes.

Non Fasting tests

Random plasma glucose tests or glucose tolerance tests are non-fasting in nature and can be conducted at any time. Usually, the oral glucose tolerance test is conducted 2-hours post meals.

Diabetes and the Fasting Plasma Glucose Test

The plasma glucose fasting test or glucose fasting plasma test is a highly preferred method to diagnose diabetes owing to its ease and convenience of administration. It is also less expensive than other tests. This is also a blood test wherein blood will be drawn from the veins. You will be required to fast for approximately 8-10 hours before checking your fasting plasma blood glucose. This test will be done to measure your glucose fasting normal range and to assess the condition.

Test name           Type                                      
Fasting blood sugar Blood drawn from the vein                
HbA1c               Blood drawn from the vein                
Glucometer           Finger prick                              
CGM                 Sensor attached to the arm                
Non-fasting tests   Blood drawn from the vein or finger prick

Tests for Gestational Diabetes

Gestational diabetes can also be diagnosed with the help of blood tests. This is the type of diabetes that occurs during pregnancy. For proper diagnosis, the test will have to be conducted between 24-28 weeks post-conception. Each woman who is pregnant may not develop gestational diabetes. In case the risk factors are high, you might be more susceptible to developing this condition. In case your sugar fasting level or random blood sugar. If the blood sugar is higher than normal in the early days of the pregnancy, it may be an indicator of type 1 or type 2 diabetes instead of gestational diabetes. Read more about the treatment for Gestational Diabetes

Glucose screening test

This test is conducted to measure your blood sugar at the time of testing. You will be required to drink a liquid that contains a certain level of glucose. 1 hour later, your blood will be drawn and tested for sugar levels. Normal results would be 140 mg/dL or lower. In case the reading is higher than that, the doctors might recommend a glucose tolerance test.

Glucose tolerance test

This test will measure your blood sugar levels before and after drinking a liquid that contains glucose. You will be asked to fast overnight before the test. After 8-10 hours of fasting, your blood sugar will be drawn to check. Furthermore, you will have to drink a liquid with glucose and then your blood sugar levels will be checked 1-, 2-, and 3 hours post-consumption. The results can differ based on the size of the glucose drink. If the level is in the normal range of fasting sugar and post-meal sugar, you need not worry. Seek help from a professional to interpret the results. Also know about sugar in urine test.


Diabetes is a disease in which the blood sugar level increases. There are 2 types of diabetes- type-1 and type-2. The person with diabetes has a blood sugar level of 126 mg/dL or above, while the fasting blood sugar normal range is 99 mg/dL by fasting blood test. Some other tests like A1C Test, Glucose Tolerance Test, Random Blood Sugar Test, Glucose


What is Diabetes?

Diabetes is the type of disease associated with the blood glucose level in the body. It occurs when the body's blood glucose or blood sugar level becomes high. Around 9.3percentof the population in the world suffers from this disease. It is of 2 types called type1 and type2 diabetes.

Blood sugar is the main source of energy. Insulin is the hormone that provides glucose to the body cells from the blood. The pancreas makes insulin. But sometimes, insulin is not used well or is not made enough, leading to glucose accumulation in our blood. This leads to a high blood sugar level. This happens in the condition of diabetes.

According to the fasting blood sugar test, the person with diabetes has 126 mg/dL or above fasting blood sugar level, which is only 99 mg/dL or below in the case of the normal blood sugar range.

How do I prepare for a fasting blood sugar test?

Do not eat or drink anything except water for 8-12 hours before the test. The best time to do fasting blood sugar test is after waking up in the morning.

Is 126 fasting blood sugar normal range?

A fasting blood sugar test is done by making the person fast for 8 to 12 hours until the test is conducted. During this duration, the person is not allowed to eat or drink anything other than water. The result of the test signifies whether a person is diagnosed with diabetes, prediabetes, or gestational diabetes. Generally, 126 mg/dL or higher fasting blood sugar means that you have diabetes. 100-125 mg/dL means the person has prediabetes and 99 MG/dL is considered normal.

What is a normal fasting blood sugar range by age?

Fasting blood sugar levels fluctuate according to the age of the person. Following is a list of normal fasting sugar levels for the different age groups of people. 

  1. Children younger than 6 months have 80 mg/dL – 180 mg/ dL as normal fasting sugar levels.
  2. Age 6-12 considered as the children and adolescents age group has 80 mg/dL-180 mg/dL fasting blood sugar as normal
  3. Age 13-19 that are the early teenage years a person with a normal fasting sugar level has a 70-150 mg/dL sugar level.
  4. The age group of 20+ years which is the adult group a person must have normal fasting blood sugar levels of less than 100 mg/dL.

What is a normal fasting blood sugar level

Fasting blood sugar levels may depend on the age of the person and the type of diagnosis. However, an approximate range of fasting blood sugar would be between 80-130mg/dL. The goal would be to reach this level in the morning as far as possible.

Can I drink water before fasting blood sugar test?

No, avoid drinking and eating before 8 to 12 hour of fasting glucose test.




This website's content is provided only for educational reasons and is not meant to be a replacement for professional medical advice. Due to individual differences, the reader should contact their physician to decide whether the material is applicable to their case.