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BUN to Creatinine Ratio Calculator

This calculator determines the ratio between Blood Urea Nitrogen (BUN) and serum creatinine levels. It's a valuable diagnostic tool used to assess kidney function and identify the underlying cause of acute kidney injury.

BUN and Creatinine Ratio Estimator

Input Fields
mg/dL
Enter your BUN level in mg/dL
mg/dL
Enter your serum creatinine level in mg/dL
If enabled, the result will update automatically when you change any value.

BUN to Creatinine Ratio Formula

Formula
$$\text{BUN to Creatinine Ratio} = \frac{\text{BUN (mg/dL)}}{\text{Creatinine (mg/dL)}}$$

Interpretation:

  • Normal Range: 10:1 to 20:1
  • 20:1 → May indicate prerenal causes (e.g., dehydration)
  • <10:1 → May suggest intrinsic renal issues or liver disease


The BUN to Creatinine Ratio is commonly used in nephrology and emergency care to distinguish between prerenal, renal, and postrenal causes of kidney dysfunction. BUN (Blood Urea Nitrogen) levels can vary due to protein intake and hydration status, while creatinine is a more stable indicator of kidney filtration. A high or low ratio helps clinicians narrow down the potential causes of acute kidney damage or chronic kidney disease.

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