BUN/Creatinine Ratio

Evaluate kidney function and identify the potential cause of acute kidney injury.

Lab Readings

BUN (Urea)

mg/dL

Creatinine

mg/dL

Disclaimer: This tool is for educational use. The BUN/Creatinine ratio is one piece of a complex clinical puzzle and must be interpreted by a physician.

Ratio Analysis

Enter your BUN and creatinine levels to calculate the ratio.

About this calculator

Overview

The ratio of Blood Urea Nitrogen (BUN) to creatinine is a blood test used to help identify the cause of kidney dysfunction. Both substances are normally filtered out of the blood by the kidneys, but they are handled differently in different states of hydration and disease.

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Pro Tips

If you are using mmol/L for Urea, remember to convert it if your Creatinine is in mg/dL (or vice versa).
The ratio is most useful when the absolute levels of BUN or Creatinine are elevated.
Always look for the 'trend' – how these numbers change over 24-48 hours during treatment.
Consider other factors like urine output and electrolyte balance when assessing kidney health.

Fun Facts

"A ratio > 20:1 often suggests a 'pre-renal' cause, such as dehydration or congestive heart failure."
"A ratio between 10:1 and 20:1 is typically considered normal or can be found in intrinsic kidney disease."
"Creatinine is a waste product of muscle metabolism, so very muscular or very frail individuals may have different 'baseline' levels."
"Urea (BUN) can be increased by high-protein diets, gastrointestinal bleeding, or certain medications like steroids."

Formula: BUN / Creatinine Ratio = BUN (mg/dL) / Creatinine (mg/dL)