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By Mayo Clinic staffYou may have a blood urea nitrogen test if your doctor suspects that you have kidney damage, or if your kidney function needs to be evaluated. If you're receiving hemodialysis or peritoneal dialysis, you may have a BUN test to help determine the effectiveness of dialysis treatment.
If kidney problems are the primary concern, when your blood is tested for urea nitrogen levels, it's likely it will also be tested for creatinine levels. Creatinine is another waste product that healthy kidneys filter out of your body in urine. High levels of creatinine may be a sign of kidney damage.
Your doctor may also order a BUN test as part of a blood test group to help diagnose a number of other conditions, such as liver failure, urinary tract obstruction, congestive heart failure or gastrointestinal bleeding. But an abnormal BUN test result alone doesn't diagnose any of these conditions.
- Blood urea nitrogen. In: Nicoll D, et al. Pocket Guide to Diagnostic Tests. 5th ed. New York, N.Y.: McGraw-Hill Companies; 2008. http://www.accessmedicine.com/popup.aspx?aID=3135548. Accessed Nov. 24, 2010.
- The kidneys and how they work. National Kidney and Urologic Diseases Information Clearinghouse. http://kidney.niddk.nih.gov/kudiseases/pubs/yourkidneys/index.htm#rate. Accessed Nov. 24, 2010.
- BUN. Lab Tests Online. http://labtestsonline.org/understanding/analytes/bun/test.html. Accessed Nov. 24, 2010.
- Stevens L, et al. Assessment of kidney function: Serum creatinine; BUN; and GFR. http://www.uptodate.com/home/index.html. Accessed Nov. 24, 2010.
- Palevsky PM. Dialysis modality and dosing strategy in acute renal failure. Seminars in Dialysis. 2006;19:165.
- Post TW, et al. Diagnostic approach to the patient with acute or chronic kidney disease. http://www.uptodate.com/home/index.html. Accessed Nov. 24, 2010.
- Laboratory reference values. Urea nitrogen (BUN). Rochester, Minn.: Mayo Foundation for Medical Education and Research; Nov. 2010.
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