Should I Fast Before Taking a Blood Test?

You might have heard about the need to fast for a certain number of hours before you can take a blood test. Fasting is crucial for such types of test as the foods you take in tend to change the results. In other words, fasting is necessary for accuracy purposes.

However, take note that not all kinds of blood tests require fasting. It is the reason why you have to consult your doctor and ask first whether you have to fast before you undergo the test. In most cases, fasting is necessary for the following:

  • Blood Glucose Fasting – You need to fast before undergoing a blood test designed to examine your blood sugar. It is mainly because all foods and drinks tend to increase the level of your blood sugar. Through fasting, a baseline estimate about what your blood sugar should be after fasting can be determined.

    Number of hours you need to fast – At least 8
  • Lipid Profile – This type of blood test will be conducted to assess your cholesterol and triglyceride level. You need to fast before you undergo this test as this will significantly increase the accuracy of the baseline readings. Note that eating something before the lipid profile test will only cause fatty substances derived from foods to get into your bloodstream, causing higher than actual readings.

    Number of hours you need to fast – 9 to 12
  • Iron Blood Test – This is also another version of the blood test, which you need to take on an empty stomach. Aside from not eating, you also need to stop taking your iron pills twenty-four hours prior to the test. It is because foods and the iron pills might alter the results, causing inaccuracy in diagnosing iron deficiency anemia or any other similar condition.

    Number of hours you need to fast – 12 hours
  • Vitamin B12 Test – The purpose of this test is to determine how much Vitamin B12 is present in your blood. The result of the test can help in diagnosing a certain kind of anemia and other health conditions. Some foods and medications tend to interfere with the accuracy of the test, so fasting is a must.

    Number of hours you need to fast – 6 to 8
  • Comprehensive or Basic Metabolic Panel – Usually a major part of a physical exam done regularly, this test aims to assess the level of your blood sugar and examine your fluid and electrolyte balance as well as your kidney and liver function. It is necessary to fast before taking this test to guarantee highly accurate results.

    Number of hours you need to fast – 10 to 12

Mentioned are just a few of the blood tests that require you to fast for a certain period. If you feel like the fasting period is too long, then the best way to handle it is to drink plenty of plain water. You need to remain as hydrated as possible during the fasting period. Also, avoid smoking, exercising, and drinking other liquids aside from water when you are fasting.

Chewing gums also need to be banned. It is because those foods and drinks can have an adverse impact on your test result. Fast based on the number of hours specified by your doctor and adhere to the medical advice he provides. That way, the test will be able to give you accurate information about your present health.

What do you think?

Written by arslan

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