Dialysis Adequacy (URR + Kt/V)

Hemodialysis adequacy: urea reduction ratio (URR) and the Daugirdas second-generation single-pool Kt/V against the KDOQI minimum targets (Daugirdas 1993).

Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.

Example

Pre-dialysis BUN
60 mg/dL
Post-dialysis BUN
18 mg/dL
Ultrafiltration volume
3 L
Dialysis session time
4 h
Post-dialysis weight
70 kg

Result: URR 70% (KDOQI target >= 65%: met); single-pool Kt/V 1.44 (KDOQI target >= 1.2: met).

The tool opens with these values already filled in. Replace them with your own.

What the result means

URR
(1 - post-BUN/pre-BUN) x 100%; KDOQI minimum >= 65%.
spKt/V
-ln(R - 0.008·t) + (4 - 3.5·R)·UF/W, R = post/pre BUN; KDOQI minimum >= 1.2 (thrice-weekly). Prescriptions vary.

What you enter

  • Pre-dialysis BUN
  • Post-dialysis BUN
  • Ultrafiltration volume
  • Dialysis session time
  • Post-dialysis weight
How this is calculated

Daugirdas JT. Second generation logarithmic estimates of single-pool variable volume Kt/V: an analysis of error. J Am Soc Nephrol. 1993;4(5):1205-1213. Read the source ↗

A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.

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Built by Clay Good. Source on GitHub.