Reference range
Conventionalratio
1020
| Specimen | Serum (calculated) |
|---|---|
| Conventional range | 10–20 ratio |
| SI range | 10–20 ratio |
| Panel | Kidney Function |
Kidney Function
BUN-to-Creatinine Ratio
Normal range 10–20 ratio. Specimen: Serum (calculated).
Also known as: BUN/Cr ratio.
10–20 ratioReference range
What is the normal range for BUN-to-Creatinine Ratio?
The standard teaching reference range for BUN-to-Creatinine Ratio is 10–20 ratio. This value is measured in serum (calculated).
Source: Adult reference values compiled from Pagana & Pagana, Mosby's Diagnostic and Laboratory Test Reference, and Fischbach & Dunning, A Manual of Laboratory and Diagnostic Tests. Reference ranges vary by laboratory, method, age, sex, and population — always use the range printed on the actual result.
Above the range
Common causes of a high BUN-to-Creatinine Ratio
- Dehydration / prerenal azotemia
- GI bleeding
- High protein intake
Below the range
Common causes of a low BUN-to-Creatinine Ratio
- Intrinsic renal disease
- Low protein intake
- Liver disease
At the bedside
Nursing considerations
- A ratio > 20:1 suggests a prerenal cause such as volume depletion.
Study aid
Your notes on BUN-to-Creatinine Ratio
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