Fasting for Blood Tests
Many blood tests require that you fast for a period of time before you take the test.
The amount of time you will have to fast for varies. Some tests only require you to fast for 2 to 4 hours, while others will require you to not eat any food for 24 hours prior to the test.
While most tests will ask you to refrain just from eating foods, a few will also require that you don’t consume any supplements or nutrients that are related to the test. For example iron blood tests require you to stop taking any iron supplements.
Why is it necessary to fast before blood work?
So the reason this step is so important is because your body needs to be in as much of a nonreactive state as possible.
If you take certain tests soon after you’ve eaten then the test results will not provide accurate readings because your body has adjusted the levels of certain body levels to accommodate the digestion and circulation of nutrients, or anti-nutrients, that were introduced into your body from food and drink.
If you fail to follow the fasting protocol your test results could show that you have a condition that you don’t in fact have. No one wants to be treated for high cholesterol when they in fact only had high cholesterol readings because of some food they ate
What do I have to avoid when I fast? Is there anything I am allowed to consume?
All foods and many medications can cause inaccurate blood readings. Some tests will also have you avoid water intake aka “dry fasting.”
If your test requires you only drink water, then you ONLY drink water.
- No gum chewing
- No coffee
- No tea
- No Juice
- No Soda
If you are required to also avoid water before your test, make sure you get enough before the fasting period to avoid dehydration. If you find that you have dry mouth try sucking on an ice cube to wet your mouth a bit. But don’t swallow the water.
If you’re worried about being hungry focus on very filling?foods right before you fast. Proteins such as meats, nuts and nut butters will satiate you for longer.
Remember that some medications can also skew results. Be sure to ask your doctor or research online for your specific test to make sure you are following the correct fasting protocol.
What common tests require fasting?
For the most part the tests which evaluate blood sugar levels and cholesterol levels will require you to fast. But there are many other factors in testing the human body, and many unique tests require certain fasting protocols.
It is not only blood tests which require fasting. If you are getting salivary tests, fecal or urine there is still a likelihood you will need to refrain from certain things. For example, many fecal tests require that you abstain from taking aspirin or ibuprofen, or any NSAID medications, for at least a 2 week period prior to the assessment.
If you are concerned about what requirements you might have for an upcoming test ask your doctor. If you would like to research the answer on your own try googling the test you are going to take, or visit True Health Labs, an online vendor, and search for your test. They have details on each test, including whether fasting is required, and what the duration of the fast should be.?