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Calculate the Urea Reduction Ratio (URR) for a single hemodialysis session: URR (%) = (Pre-BUN − Post-BUN) / Pre-BUN × 100. KDOQI recommends a minimum URR ≥65% and a target dose ≥70%. URR is a simple adequacy marker but is being phased out in favor of Kt/V, which also accounts for urea generation and volume contraction. Derived from the KDOQI Clinical Practice Guideline for Hemodialysis Adequacy. Valid for single hemodialysis sessions with BUN drawn pre- and immediately post-treatment; not for peritoneal dialysis. Not medical advice.
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Tool usage guide
Calculate the Urea Reduction Ratio (URR) for one hemodialysis session using pre-dialysis and post-dialysis BUN values. The calculator applies URR = (Pre-BUN − Post-BUN) / Pre-BUN × 100% and compares the result with KDOQI reference thresholds of 65% minimum and 70% target. This tool is not medical advice.
Background
A single hemodialysis session has a pre-dialysis BUN of 90 mg/dL and a post-dialysis BUN of 27 mg/dL.
Problem
Calculate the percentage reduction and determine whether it meets the KDOQI target.
How to use
Enter 90 for Pre-dialysis BUN, 27 for Post-dialysis BUN, and use 4 decimal places.
{"preBun":90,"postBun":27,"decimalPlaces":4}Outcome
The calculator returns URR = 70.0000%, with the status Target met (≥70%).
Background
A hemodialysis session has a pre-dialysis BUN of 80 mg/dL and a post-dialysis BUN of 30 mg/dL.
Problem
Check whether the calculated URR meets the minimum KDOQI reference value.
How to use
Enter 80 for Pre-dialysis BUN, 30 for Post-dialysis BUN, and use 4 decimal places.
URR (%) = (Pre-BUN − Post-BUN) / Pre-BUN × 100.
The referenced KDOQI thresholds are a minimum of 65% and a target of 70% or higher.
It requires pre-dialysis BUN and post-dialysis BUN values in mg/dL. Decimal places are optional.
No. This calculator is intended for a single hemodialysis session.
No. URR is a simple marker and does not account for urea generation or volume contraction; Kt/V should be used to confirm full adequacy.
{"preBun":80,"postBun":30,"decimalPlaces":4}Outcome
The calculator returns URR = 62.5000%, with the status Below minimum (<65%).