Blood Urea Nitrogen

BUN (Blood Urea Nitrogen), BUN:Creatinine Ratio, Urea Nitrogen, Blood

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Taking medicines, such as amphotericin B (such as Fungizone), nafcillin, aminoglycosides (such as Garramycin), and tobramycin (Tobrex), corticosteroids, tetracycline antibiotics, and rarely, the antibiotic chloramphenicol (Chloromycetin or Pentamycetin).
• Taking diuretics, which can cause dehydration.
• Your age. BUN levels rise as you get older.
• Your sex. Women and children have lower BUN levels than men.

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Author:	Jan Nissl, RN, BS Sydney Youngerman-Cole, RN, BSN, RNC	Last Updated: November 21, 2006
Medical Review:	Patrice Burgess, MD - Family Medicine Andrew Swan, MD, CCFP, FCFP - Family Medicine
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