Kidney system

BUN : Creatinine Ratio

BUN / Cr

A ratio that helps distinguish causes of elevated BUN.

What is it

BUN : Creatinine Ratio — in plain English.

The BUN-to-creatinine ratio helps distinguish kidney-based versus hydration-based causes of BUN elevation.

Why it's measured

What BUN / Cr can reveal.

The BUN/creatinine ratio has been used in research and clinical practice to interpret kidney panel findings.

Reference range

Where most laboratories draw the standard line.

Standard laboratory reference

10 – 20 ratio

Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.

What results may indicate

Higher vs. lower BUN / Cr — at a high level.

Elevated

Higher ratios have been associated with dehydration or GI bleeding in research literature.

Lower

Lower ratios may reflect low protein intake or certain liver conditions.

These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.

When it's measured

When BUN / Cr is typically run.

Calculated from BUN and creatinine.

Related markers

Often measured alongside BUN / Cr.

Measured in

BUN / Cr is one of 160 biomarkers in the Apex Panel.

A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.

Explore the Apex Panel
160 biomarkers13 body systemsPhysician-reviewed
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This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.