Know Your Blood Parameter: BUN/Creatinine Ratio

1. Parameter Name 

BUN: Creatinine Ratio

2. Test Type 

Blood

3. Normal Range

• Typical Range: 10:1 to 20:1 (May vary slightly based on the lab)

4. High Levels Indicate 

May indicate dehydration, gastrointestinal bleeding, high protein intake, or catabolic states. A high ratio with elevated BUN and normal creatinine often suggests prerenal causes.

5. Low Levels Indicate 

May suggest liver disease, malnutrition, or acute tubular necrosis where creatinine rises disproportionately compared to BUN.

6. Why It's Tested 

Used to differentiate between types of kidney dysfunction (prerenal vs. renal), assess hydration status, and interpret causes of abnormal kidney function tests.

7. Associated Symptoms (if abnormal) Depend on the underlying cause:

• High: Dehydration signs (dry mouth, low urine output)

• Low: Fatigue, loss of appetite, edema (if due to kidney or liver disease)

8. What To Do If Abnormal 

Review hydration, protein intake, medications. Consider repeat testing and evaluate kidney and liver function. Consult with a nephrologist if needed.

9. Common Conditions Related 

Dehydration, gastrointestinal bleeding, acute kidney injury, liver disease, and malnutrition.

10. Nutrition or Lifestyle Connection 

Ensure adequate hydration, avoid excess protein intake if not advised, manage chronic conditions affecting kidneys or liver.

11. References (APA Format)

•  Pagana, K. D., & Pagana, T. J. (2021). Mosby’s Diagnostic and Laboratory Test Reference (15th ed.). Elsevier.