Metabolic Health

Fasting Blood Sugar Test

Reviewed by

Shifa Fathima

What is Fasting Blood Sugar Test?

A Fasting Blood Sugar Test is used to measure the sugar level in the blood. Before this test, the person is strictly warned to not eat or drink anything except water for 8 to 12 hours. This test is used to diagnose prediabetes, diabetes, or gestational diabetes. It is safe and common, so there is no need to worry.

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.

Fasting Blood Sugar level for people with diabetes, prediabetes, and normal people.

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 lower is normal.

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 9.3percent of 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.

When to get a Fasting 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 blood sugar level test, after 8-12 hours of not eating or drinking anything except water.

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What are the other types of Blood Sugar Tests?

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 fasting blood sugar test 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.

1. 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

2. 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:-


1. Are there any risks with a fasting blood sugar test?

It is common, easy and safe to find the fasting blood sugar level. There is no risk with this test.

2. When will I get the results of the test?

You will get the result of the test after one or two days. 

3. 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 the test is after waking up in the morning. 

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