Fasting Instructions for Blood Test

Are you going in for a blood test? And fasting instructions for blood tests specified by your laboratory technician seem to be confusing? Then read the article below for proper blood test fasting instructions before your appointment.
Whenever a patient is prescribed a blood test, it is important to fast for a particular amount of time before the test is taken. Usually, the doctor does explain, elaborately, all the necessary instructions you may need to comply with. However, the blood tests and the testing parameters for every patient differ based on the underlying condition. Thus, the instructions on fasting before a blood test can slightly vary.

How to Fast Before the Test

Many times, patients may wonder as to what or why is fasting so important? Well, the reason is that certain tests can be sensitive to particular types of food and beverages. Which is why, patients are asked to fast for 8 or 12 hours before getting the tests done. And since there are various types of blood tests done like blood glucose, complete blood count (CBC), cholesterol levels, triglycerides, chemistry tests, enzyme tests, etc., you need to be thoroughly clear about instructions for fasting before a blood test. Basically, blood glucose, vitamin tests, cholesterol levels, triglycerides, and other specialized blood tests require fasting. If you have a scheduled appointment for blood test, perhaps we can help you prepare for the test with the proper instructions which are mentioned below.
  • While fasting, specifically when it's for cholesterol and triglyceride screening, the recommended duration is 12 hours. Other tests like vitamin and glucose levels only require 8 hours of fasting.
  • You can drink small amounts of water, but avoid fruit juices, tea, and coffee (caffeine can change test results). However, some tests can allow black tea or coffee without sugar.
  • If you have any regular medication that has to be taken, you can ask your doctor if it is allowed.
  • Chewing gum, specifically the ones with sugar in it, are strictly not permissible. Any type of liquid, besides water, going into your system is not allowed before any blood test. These instructions should be taken very seriously.
  • You cannot smoke before taking the tests as well. Just as fasting, you have to refrain from smoking for the same duration.
  • Another fasting rule for blood test includes no exercise. Working out is not advised before the blood test because it can alter the test results.
  • If you are asked to fast for 12 hours, stop taking in any foods and beverages from 7 p.m. So that the next day, you can get up early and get your tests done.
  • Also, doctors will advice you to keep a check on what kind of food you are eating throughout the week. Avoid eating eggs, red meat, and any high-cholesterol and high-fat foods.
  • However, for a routine cholesterol test, don't change your diet drastically. In this test, your doctor wishes to know what your current cholesterol level is according to the diet you follow on a regular basis.
These were some critical blood test fasting instructions that should be kept in mind at all times. But you may be wondering about what might happen if let's say you forgot or didn't follow these rules. The most important setback you will get by not fasting before a blood test is that your tests won't be accurate. Your doctor will get the misguided tests and might just give you inaccurate treatment methods and/or medication. The tests might show that you have diabetes or high cholesterol, which you perhaps don't, and may be advised wrong prescriptions. And finally, you will have to fast all over again (properly) and take the tests once more.

Remember, don't look at fasting as something your doctor's or physician's way to add to your agony. It is an essential factor for blood test. Although you may find the process slightly tough, what you need to keep in mind is the end result. It is your job as well to make sure that your tests are as accurate as possible. And perhaps this is one of the ways you can contribute to your own good health.
By Sheetal Mandora
Last Updated: 9/30/2011
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