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Calculates single-pool Kt/V (spKt/V) for hemodialysis adequacy using the Daugirdas second-generation formula. KDOQI defines a minimum delivered spKt/V of 1.2 per treatment for patients treated three times weekly, with a target of 1.4.
spKt/V = −ln(R − 0.008 × t) + (4 − 3.5 × R) × (UF ÷ W) where R = post/pre BUN ratio, t = treatment time (h), UF = ultrafiltrate (L), W = post-dialysis weight (kg)
≥ 1.2 (KDOQI minimum delivered dose; target 1.4)
Single-pool Kt/V (spKt/V) is the standard measure of hemodialysis urea removal. The Daugirdas second-generation equation corrects for ultrafiltration and treatment time and is the KDOQI-recommended method.
Specialty
NephrologyCategory
NephrologyDifficulty
Basic
Estimated Time
30 seconds
Version
1.0
Last Updated
2026-08-16
Formula
Keywords
Normal Range
≥ 1.2 (KDOQI minimum delivered dose; target 1.4)
| Classification | Range |
|---|---|
Adequate thrice-weekly hemodialysis (KDOQI) | ≥ 1.2 |
Below target thrice-weekly hemodialysis | 1.0–1.19 |
Inadequate thrice-weekly hemodialysis | < 1.0 |
Calculates single-pool Kt/V (spKt/V) for hemodialysis adequacy using the Daugirdas second-generation formula, supporting KDOQI dialysis dosing standards.
KDOQI recommends a minimum delivered spKt/V of 1.2 per treatment (target 1.4) for three-times-weekly hemodialysis. Below 1.0 indicates inadequate dialysis.
Dialysis dose is directly linked to patient survival and quality of life. spKt/V is the KDOQI-recommended measure for verifying that patients receive an adequate minimum delivered dose.
A 68-year-old man on thrice-weekly hemodialysis: pre-BUN 90 mg/dL, post-BUN 30 mg/dL, ultrafiltrate 2.5 L, treatment time 4 h, post-dialysis weight 75 kg.
Inputs:
R = 30/90 = 0.333; spKt/V = −ln(0.333 − 0.032) + (4 − 1.167) × 2.5/75 ≈ 1.29 — adequate (≥ 1.2).
spKt/V ignores post-dialysis urea rebound; eKt/V corrects for it. The difference is small at lower doses and grows at higher doses. spKt/V is the KDOQI standard for routine monitoring.
No. Peritoneal dialysis adequacy uses weekly Kt/V targets (e.g., ≥ 1.7/week) with a different calculation.
Chronic kidney disease staging
Laboratory-reported eGFR
Medication dose adjustment
Disclaimer: This calculator is intended for educational and clinical decision support purposes only. Dialysis adequacy decisions must incorporate the prescription, access function, patient status, and KDOQI guidelines.