End
BUN/Creatinine Ratio
Utilize as part of a workup for renal disease to help differentiate prerenal azotemia from other causes of kidney impairment.
Blood Urea Nitrogen (BUN)
mg/dL
Serum Creatinine (Cr)
mg/dL
0
Ratio
Calculating…
| Ratio | Interpretation |
|---|---|
| < 10 | Intrarenal (intrinsic) kidney injury or decreased urea synthesis. |
| 10 – 20 | Normal range or postrenal etiology. |
| > 20 | Suggestive of prerenal azotemia (e.g., dehydration, hypoperfusion). |
1
Prerenal Azotemia: If BUN:Cr > 20, this may be a sign of prerenal azotemia. If clinically appropriate, consider additional workup to determine cause.
2
Multifactorial BUN: BUN can be impacted by other physiologic processes outside of the kidney (e.g., GI bleeding, high protein intake, corticosteroid use); a BUN value alone should not be used as the sole indicator of renal health.
