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BUN:Creatinine Ratio Helpful for Diagnosing Hypovolemia and GI Bleed

Lin, Michelle MD

doi: 10.1097/01.EEM.0000731772.49673.02
    BUN, creatinine, hypovolemia, GI bleed

    The BUN:creatinine ratio is a helpful calculation. Traditional teaching states that hypovolemia should be considered if the ratio is higher than 20:1. A ratio of more than 30:1 should prompt concern for an upper gastrointestinal bleed (a likelihood ratio of 7.5) based on a systematic review. (JAMA. 2012;307[10]:1072;

    This makes sense because blood is digested to protein and is then metabolized to BUN in the urea cycle within the liver.

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    Dr. Linis the founder, CEO, and editor-in-chief of Academic Life in Emergency Medicine ( and a professor of emergency medicine at the University of California San Francisco with interests in health professions education and digital scholarship. Follow her on Instagram@MichelleLinMDand on Twitter@M_Lin.

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