Assess dialysis adequacy using the Urea Reduction Ratio.
Urea Measurements (BUN)
mg/dL
mg/dL
Dialysis Efficiency
Calculated URR70.0%
Adequate Dialysis (≥ 65%)
Clearance Metric
About this calculator
Overview
The Urea Reduction Ratio (URR) is a simple way to measure the adequacy of a hemodialysis treatment. It measures how much urea (a waste product) was removed from the blood during a single dialysis session.
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Pro Tips
Ensure the 'post' sample is taken correctly after the blood pump has been slowed or stopped to avoid 'rebound' urea dilution.
URR is often used alongside Kt/V for a more complete picture of dialysis dose.
If URR is consistently low, consider checking hemodialyzer efficiency, blood flow rates, or vascular access recirculation.
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Fun Facts
"A common clinical target for URR is ≥ 65%."
"A higher URR generally translates to better long-term outcomes for patients on hemodialysis."
"URR only accounts for urea removal and doesn't consider fluid removal or session time (unlike Kt/V)."
