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  BUNDefinitionBUN stands for blood urea nitrogen. Urea nitrogen is what forms when protein breaks down. A test can be done to measure the amount of urea nitrogen in the blood. Alternative NamesBlood urea nitrogenHow the Test is PerformedBlood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to fill with blood. A needle is inserted into the vein, and the blood is collected in an airtight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding. In infants and young children, the area is cleaned with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any continued bleeding. How to Prepare for the TestSome drugs affect BUN levels. Before having this test, make sure the health care provider knows which medications you are taking. Drugs that can increase BUN measurements include:
Drugs that can decrease BUN measurements include:
How the Test Will FeelWhen the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing. Why the Test is PerformedThe BUN test is often done to check kidney function. Normal Results7 - 20 mg/dl. Note that normal values may vary among different laboratories. What Abnormal Results MeanHigher-than-normal levels may be due to:
Lower-than-normal levels may be due to:
Additional conditions under which the test may be done include:
RisksVeins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others. Other risks are slight but may include:
ConsiderationsFor people with liver disease, the BUN level may be low even if the kidneys are normal.
Review Date:
5/15/2007 Reviewed By: Robert Mushnick, M.D., Clinical Assistant Professor, Department of Nephrology, SUNY Downstate Health Center, Brooklyn, NY. Review provided by VeriMed Healthcare Network. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-
A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.  |
