Usually before undergoing blood tests the doctor has always asked you to stay hungry which means that you are not allowed to eat anything until and unless you have had not undergone a blood test. You might have noticed that all the blood tests are carried out early in the morning because it is easy to fast in the morning, but the question is why fasting for blood work is mandatory?

If you have already eaten anything, and then you have taken the blood test, then the circulating triglycerides and cholesterol will have a high level that will interact with the lab results. In the same way, if you have eaten something sweet, the circulating carbs will alter the lab results.

Mentioned below are the rules that why one should fast before lab tests.

Things to do Before Blood Test

Fasting for Blood Tests: Rules and Guidelines

  • Before the blood test, the patient should not eat or drink. However, water is the only thing that the patient must consume.
  • Eating must be prohibited at least 8 hours before the test.
  • For lipid profiling the patient must not eat anything for at least 12 hours before the tests but water is allowed.
  • Workout, smoking or chewing gums are not allowed because such activities will excite the metabolic rate and will surely modify the results of the lab testing.
  • Alcohol consumption should be stopped before one day at least.
  • Only particular medication is allowed before blood tests. In the case of lipid test, one must avoid the use of birth control pills because these pills are meant to increase the serum cholesterol level which will change the tests readings.
  • It is important to fast for about 12 hours but make sure you do not fast beyond 14 hours. Fasting for this long has an adverse impact on the lab test results.
  • While fasting keep on drinking much water and stay hydrated.

Fasting is essential for many blood tests because when you eat something the carbs, proteins or fats may enter into your blood and alter the results completely.

Types and Instruction for Various Blood Test

The instructions or guideline for the different tests varies. If the doctor has asked you to fast for at least 12 hours before the blood test, then he might ask you to eat something before a lipid test. So the guidelines for a different kind of testing vary.

Fasting for Blood Work Glucose Test

Fasting for blood work for at least 8 to 12 hours before the test is mandatory. The test is usually performed for the detection of diabetes so eating anything will alter the results. However, only water is allowed.

Iron Blood Test

This test is carried out in the morning and a fasting state. For this trial, one must skip the iron pills one day before the test. If you are taking the pills, then an increased iron level will be detected in your blood, and it will modify the lab findings. This test is performed to diagnose anemia and other iron deficiency linked diseases.

Lipid Profile

Lipid profile testing is carried out to check the level of LDL, HDL, and IDL in your blood. These are various kinds of cholesterol. You must avoid any food at least 12 hours before the test is conducted.  Fasting is essential in such sort of tests.

Gamma-Glutamyl Transferase Test

This test is conducted to diagnose any liver disease. Things to be avoided before this test include alcohol, smoking, and food. These three things if taken will alter the results to the great extent, and the problem will not be diagnosed on time.

Things to be Done During a Lab Test

  • For a lipid profile test, fasting is mandatory. The person who is responsible for the test will clean the area, insert the needle and will withdraw the little amount of the blood from the veins. He might tie an elastic band around the arm to aid the withdrawing process. After the blood has been taken the puncture site is usually covered with a bandage. The whole procedure does not take more than few minutes. The blood sample is then sent to the lab, and the results are generated within few days.
  • After the test is done special care must be taken. Before any activity, eat something healthy that gives you energy. You can continue with the daily chores in a usual manner.
  • Once the reports are out, your doctor will call you to discuss the results. If anything unusual is detected in your report, then the doctor will suggest the care plan and treatment plan.
  • The patient will have to act upon the instructions given by the doctor.

So now the fasting for blood work has been cleared.