Chemistry Screen

How To Prepare

How you prepare for a chemistry screen depends on what your doctor is looking for in the test.

• You may be instructed not to eat or drink anything except water for 9 to 12 hours before having your blood drawn. This is called a "fasting blood test." Fasting is not always necessary, but it may be recommended.
• Usually, you are allowed to take your medicines with water the morning of the test.
• Do not eat high-fat foods the night before the test.
• Do not drink alcohol before you have this test.

Many medicines may change the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

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Author:	Maria G. Essig, MS, ELS	Last Updated: April 17, 2008
Medical Review:	Kathleen Romito, MD - Family Medicine Brian D. O'Brien, MD - Internal Medicine
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