What does a BUN/creatinine ratio of 24, 25, or 30 mean?

Ratios in the 24 to 30 range are elevated and usually point to dehydration or reduced blood flow to the kidneys (prerenal cause), not intrinsic kidney disease. Hydrating well and rechecking often resolves it. Persistently high ratios warrant a workup for GI bleeding, heart failure, or high-dose protein intake.

What does a BUN/creatinine ratio of 8 mean?

A ratio of 8 is slightly below the typical normal range (10 to 20). It is usually caused by a low-protein diet, liver disease (less urea production), or high muscle mass (which raises creatinine and lowers the ratio). It is rarely concerning on its own.

What symptoms come with a high BUN/creatinine ratio?

The ratio itself causes no symptoms. The usual underlying cause (dehydration) brings thirst, dark urine, dizziness, and fatigue. Less commonly, GI bleeding can drive the ratio up and cause black or tarry stools, lightheadedness, or visible blood in stool or vomit.

BUN/Creatinine Ratio: Normal Range, What It Means, How to Test | Empirical Health

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BUN/Creatinine Ratio

Normal range: 10 – 20 (lower is better)

The BUN/creatinine ratio helps your doctor figure out why kidney markers might be off. A high ratio with elevated BUN suggests the kidneys themselves are healthy but not getting enough blood flow (often from dehydration). A normal ratio alongside elevated creatinine points to actual kidney disease. It is a diagnostic clue, not a standalone test.

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What can cause high BUN/Cr Ratio?

A normal BUN/Cr Ratio is 10 – 20. Lower is better.

A high BUN/creatinine ratio usually indicates dehydration or reduced blood flow to the kidneys (called prerenal azotemia), meaning the kidneys are structurally healthy but underperfused. GI bleeding and high-protein diets also raise BUN selectively, pushing the ratio up.

A low ratio may indicate liver disease (reduced urea production), malnutrition, or rhabdomyolysis (muscle breakdown floods the blood with creatinine). Because this is a derived ratio, the same lifestyle factors and medications that affect BUN and creatinine individually drive changes here. Staying hydrated is the single most impactful thing you can do.

The BUN/creatinine ratio helps your doctor figure out why kidney markers might be off. A high ratio with elevated BUN suggests the kidneys are healthy but not getting enough blood flow (often from dehydration). A normal ratio alongside elevated creatinine points to actual kidney disease. It is a diagnostic clue, not a standalone test.

How does BUN/Creatinine Ratio change with age?

BUN/Creatinine Ratio tends to rise with age (correlation with age, r = +0.19). The chart below shows the median by 5-year age bin and a linear trend line.

BUN/Creatinine Ratio rises with age, chart with median and linear trend

Biomarkers related to BUN/Cr Ratio

BUN/Cr Ratio is most highly correlated with BUN and HDL Cholesterol. Here are the top biomarkers correlated with BUN/Cr Ratio, based on 500,000 tests done by Empirical Health.

The percentage shows how strongly two biomarkers move together. A higher number means the relationship is stronger. Green = rises and falls together. Orange = one rises as the other falls.

Frequently asked questions about BUN/Cr Ratio

BUN/Cr Ratio test cost

BUN/Cr Ratio is a calculated value, so it's included whenever you run a comprehensive metabolic panel (about $29–$55 at Quest or LabCorp). It also comes in a 100+ biomarker panel from Empirical Health for $190.

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Where to test BUN/Cr Ratio

You can measure your BUN/Cr Ratio for at 2,200+ testing locations across the US. Click below and enter your zip code to browse locations near you.

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