One of the most important things in determining the accuracy and reliability of your laboratory test is you, the individual. 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 are useful:

1. Follow instructions, if there are any, to prepare for the specific test you are having performed
2. Alert the person collecting your sample if you have not followed the instructions and how you did not
3. Inform your doctor of any medications (including herbal remedies, vitamins and supplements) you might currently be taking or particular foods you have eaten within the day prior to the test.

Many tests require no special preparation, but for those that do, be certain to keep to the instructions given. If you are ever unclear about the instructions, be sure to ask the person ordering the test for clarification.

Some of the more common types of preparation required for testing include fasting (going 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 in the 10 to12 hours before the test. There may be some foods and medications you will need to avoid which you will be told about, or you may be asked not to smoke before the test.

Examples of some frequent laboratory tests that require advance preparation include:

• Glucose tolerance, when samples are taken while fasting and two 2 hours after food
• Blood glucose tests, when you may be asked to fast , or eat meals at set times prior to having your blood test
• Faecal occult blood test, when you are asked not to take certain foods and medications
• Serum lipids (triglycerides, cholesterol, etc.) – overnight fasting may be required

On Lab Tests Online, we provide general information about test preparations that 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 doctor for his or her instructions, rather than relying on the information on this or other web sites, as different testing laboratories may have varying procedures (protocols).

Finally, with pathology 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, tell them about any medications that you are taking at the time of testing, including herbal remedies and supplements, 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 helps to ensure the reliability of your test results.

Sources and Links

South Bend Medical Foundation, Inc.: Patient Information: Pre-Test Requirements - another good example

Consumer Laboratory Testing Information Page