What this marker measures
The ratio is a context clue clinicians use to distinguish "pre-renal" patterns (dehydration etc.) from intrinsic kidney patterns. It is never used in isolation — diagnosis usually requires confirmation and clinical context based on the full panel.
High or low: what it can mean
High BUN/Creatinine Ratio
A high ratio (often above 20) is sometimes seen with dehydration, GI bleeding, or a high-protein diet rather than a kidney filtration issue itself. It is often reviewed with creatinine, eGFR, BUN, electrolytes, and clinical context.
Read full explanation →
Low BUN/Creatinine Ratio
A low ratio (often below 10) can be seen with a low-protein diet, liver-related changes in urea production, or rhabdomyolysis (which raises creatinine relative to BUN). Interpretation always belongs with the broader clinical picture.
Read full explanation →
Frequently asked questions
What is BUN/Creatinine Ratio?
+
The BUN/creatinine ratio compares blood urea nitrogen to creatinine. It is a calculated value, not a directly measured one, and is most useful when read together with the individual BUN and creatinine results.
What does BUN/Creatinine Ratio measure?
+
The ratio is a context clue clinicians use to distinguish "pre-renal" patterns (dehydration etc.) from intrinsic kidney patterns. It is never used in isolation — diagnosis usually requires confirmation and clinical context based on the full panel.
What does high BUN/Creatinine Ratio mean?
+
A high ratio (often above 20) is sometimes seen with dehydration, GI bleeding, or a high-protein diet rather than a kidney filtration issue itself. It is often reviewed with creatinine, eGFR, BUN, electrolytes, and clinical context.
What does low BUN/Creatinine Ratio mean?
+
A low ratio (often below 10) can be seen with a low-protein diet, liver-related changes in urea production, or rhabdomyolysis (which raises creatinine relative to BUN). Interpretation always belongs with the broader clinical picture.
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.