What is the significance of an elevated Blood Urea Nitrogen (BUN) level of 47, indicating impaired renal function?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 17, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

A BUN level of 47 mg/dL is significantly elevated and concerning, indicating potential kidney dysfunction that requires prompt medical attention. This elevation suggests that the kidneys may not be effectively filtering waste products from the blood, and it is essential to contact a healthcare provider immediately for evaluation. The healthcare provider will likely order additional tests, including creatinine levels, to calculate the glomerular filtration rate (GFR) and assess overall kidney function, as recommended by the National Kidney Foundation practice guidelines for chronic kidney disease: evaluation, classification, and stratification 1.

Some key points to consider:

  • Normal BUN levels typically range from 7 to 20 mg/dL, and an elevation above this range can indicate kidney dysfunction or other conditions such as dehydration, gastrointestinal bleeding, or heart failure.
  • The elevated BUN occurs because urea, a waste product from protein metabolism, accumulates when kidneys aren't functioning properly.
  • Treatment depends on the underlying cause but might include medication adjustments, dietary changes (particularly reducing protein intake), managing blood pressure, and ensuring adequate hydration.
  • A comprehensive evaluation is essential to determine the specific cause and appropriate treatment, as chronic kidney disease can lead to complications such as hypertension, cardiovascular disease, bone disease, and anemia, as noted in the acr appropriateness criteria® renal failure study 1.

It is crucial to address the elevated BUN level promptly to prevent potential complications and ensure the best possible outcome in terms of morbidity, mortality, and quality of life.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.