• Fasting (not eating any or certain foods) for several hours or even overnight
• Drinking more or less water than usual
• Avoiding certain medications or vitamin and herbal supplements prior to testing. It is important to talk to your doctor about the medications you are currently taking (including supplements and other over-the-counter medications) before making changes prior to having laboratory tests performed.

If you are delivering a specimen to the lab, there might be special instructions for transporting the specimen. Your physician should provide you with written instructions for preparing for your test. Follow those instructions exactly as they are written. If you are not certain if special preparation is required, or if you have questions about the instructions you were given, contact your physician’s office.

If you did not follow the test preparation instructions you received from your physician, let the staff at the specimen collection lab know about this before your specimen is collected.