One of the most important factors in determining the
accuracy and reliability of your lab test is you, the patient. After all, it is a sample from your body (blood, urine, or some other specimen) on which the test will be performed. Therefore, it is essential that you do the following to ensure that the results will be useful:
- Follow instructions, if there are any, to prepare for the specific test you are having performed;
- Alert the person collecting your sample if you have deviated from the instructions and how;
- Inform your health care provider of any medications (including herbal remedies) you might currently be taking or foods you have eaten within the day prior to the test.
Other behaviors may also alter some test results, such as excessive exercise, dehydration, excessive eating, or recent sexual activity.
It should be noted that many tests require no special preparation. But for those that do, be certain to adhere to the instructions provided. If you are ever unclear about the instructions, be sure to ask the person ordering the test for clarification.
To help you remember what you need to do before having a lab test, your provider should give you a written copy of instructions, if there are any. In fact, all laboratories that perform moderate and/or highly complex tests are required by the federal government under the Clinical Laboratory Improvement Amendments (CLIA) to provide patients with such written policies. You also may find information about preparations needed for specific tests on Internet sites, such as this one. Nonetheless, you should always follow your health care provider's instructions, as the procedures for a particular test might vary from one lab to another.
Some of the more common types of preparation required for testing include fasting (to go without all or certain foods) for several hours before the test or even overnight. Certain tests may require you to increase or decrease the amount you drink for 10 to12 hours ahead of the test. There may be specific foods and medications you will need to avoid. You even may be asked not to smoke before the test. You could be asked to follow certain procedures to transport a specimen (such as urine, feces, or semen) from home to the lab.
Examples of some frequent laboratory tests that require advance preparation include:
On Lab Tests Online, we provide general information about test preparations you may need to follow before taking certain tests. This information is usually included in the "Is there anything else I should know?" section under "The Test" tab in our test descriptions. However, please be sure to check with your provider for their instructions rather than relying on the information on this or other web sites, as different labs may have varying testing protocols.
Finally, with laboratory testing, like other aspects of medical care, it is crucial that you are open and honest with your health care provider. Just as you should give them your complete personal, medical, and family history, you may need to report any medications that you are taking at the time of testing, including herbal remedies, as these can affect the results. You also may be asked about the amount of alcohol you consume or tobacco products you smoke. Providing complete, accurate information will help to ensure the reliability of your test results.
Sources and Links:
Main Line Clinical Laboratories: Patient Preparation Guide - a good example of a lab that clearly spells out steps patient should take in preparation for testing
South Bend Medical Foundation, Inc.: Patient Information: Pre-Test Requirements - another good example
Patient Test Management For Moderate or High Complexity Testing, or Both
Consumer Laboratory Testing Information Page
