🩺 Urea Reduction Ratio (URR)
UseWhen to use: quick HD adequacy screen when only pre/post BUN are available.
StrataCommon teaching target ≥65% for thrice-weekly HD — prefer Kt/V when data allow.
LimitsWhen not to use: post-BUN drawn after rebound. · Pitfall: unit mismatch. · Ignores UF/time.
SourceStandard URR definition
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
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Methodology · worked example, guidelines & full notes
100×(1−R).
When to use
When to use: quick HD adequacy screen when only pre/post BUN are available.
How it works
URR = 100 × (1 − Cpost/Cpre).
Key points
- 100×(1−R).
- Simple adequacy cue.
- Next: spKt/V.
References
- Standard URR definition
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Pre-dialysis BUN / urea | 60 same units |
|---|---|
| Post-dialysis BUN / urea | 18 same units |
→URR70.0%
- Cpost/Cpre：0.300
- Cue：>=65% — common URR adequacy cue (thrice-weekly context)
Verification & sources · governance
FAQ
Frequently asked questions
- Does Urea Reduction Ratio (URR) upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is Urea Reduction Ratio (URR) calculated in practice? Can you show a worked example?
- Inputs: Pre-dialysis BUN / urea 60 same units, Post-dialysis BUN / urea 18 same units → Result: URR 70.0 %（Cpost/Cpre: 0.300, Cue: >=65% — common URR adequacy cue (thrice-weekly context)）