Why We Need Fasting For Blood Test?


Fasting for blood test is required for number of reasons. And it has been the customary prerequisite for the determination of the medical condition. There may be reasons which in the impulse may not seem logical. But, according to the latest research it is meaningful source of finding the illness in depth.

Fasting For Blood Test

Fasting for Blood Test – Frequently Asked Questions

Here, in this article, you will get to find the answers of some very common questions which are listed below:

  1. Why it is important to fast before blood test?

Blood contains particular changes in the iron, lipids and glucose levels after having food. To remove those elements and uncommon levels of iron, etc. you should fast for minimum 10 hours. What it helps in is to get the correct lab report.

  1. What actually may happen if you don’t fast for blood test?

If you won’t do as needful which is fasting, the results may not be accurate. On the basis of which absolute treatment may not be given again resulting in other complications. In case of emergency where it is about you being fainted, it is better to take something. But then it is your responsibility to take the step and let the person who will take the blood test know about it.

  1. Does fasting include abstinence of water and food?

Well, food is something you have to skip for ten to twelve hours. However, you can certainly drink water as much as you want. But that doesn’t mean you can take beverages, caffeinated drinks, liquor, sodas or colas. And you have to wait till blood is tested.

  1. Which blood tests require fasting?

Here is a list of those tests which require fasting:

–           Lipid profiles.

–           Diabetes.

–           Glucose.

–           Common glucose tolerance.

–           Glucose tolerance during pregnancy.

Doctors ask for fasting prior other blood tests too. This is perhaps when you are uncertain about the reason, why. For that, you should ask about the reason why fasting is required.

Some Important Key Points for Fasting

You must be sure about the following instructions which are commonly given before asking for fasting.

  • For the cholesterol check you shouldn’t have food at all, however, water is what you can take without any second thought. This fasting has to be carried out for ten hours.
  • When the blood test is for glucose or homocysteine or iron then again you can’t have food. However, water is what you can have. The fasting is for minimum eight hours.
  • To get GTT (glucose tolerance test) in a non-pregnant body, you can’t have anything to drink including water or any sort of food. This fasting is for 8 hours.
  • Last but not the least, for the H-Pylori sniff (breath) test, you can’t have food or water in any form. The fasting is for four hours.


All in all, there are fasting instructions for couple of blood tests. These enable to draw the right calculation and helps in treating according to the lab reports. Moreover, instructions before each and every fasting for blood test are mentioned before the test. So, you don’t have to fret about if you have to fast or not.

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