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Calcimator

Dialysis Adequacy (spKt/V) Calculator

Single-pool Kt/V from pre/post dialysis BUN.

Inputs

Results

Single-Pool Kt/V

1.3

Urea Reduction Ratio (URR)66.7%
Equilibrated Kt/V1.14
Adequacy Met (1=Yes, 0=No)1
Weekly Std Kt V3.9
Std Kt V589.86
Std Kt V Approx3.41
How to Use This Calculator
  1. Enter pre-dialysis BUN (mg/dL) and post-dialysis BUN (mg/dL) from session labs.
  2. Enter session duration (hours) and ultrafiltration volume (L) removed during dialysis.
  3. Enter post-dialysis weight (kg).
  4. Read the single-pool Kt/V (spKt/V): KDOQI target >= 1.2 for thrice-weekly hemodialysis.
  5. Check URR (%) — target >= 65% — and whether adequacy was met (1 = yes, 0 = no).

How the result changes with Pre-Dialysis BUN (mg/dL)

Pre-Dialysis BUN (mg/dL)Single-Pool Kt/V
310.55
1061.97
1952.78
2703.3

What each input means

Pre-Dialysis BUN (mg/dL)
Blood urea nitrogen before dialysis session.
Post-Dialysis BUN (mg/dL)
Blood urea nitrogen after dialysis session.
Session Duration (hours)
Duration of the hemodialysis session.
Ultrafiltration Volume (L)
Volume of fluid removed during dialysis.
Post-Dialysis Weight (kg)
Patient weight after dialysis.

What each result means

Single-Pool Kt/V
Daugirdas 2nd-gen spKt/V. KDOQI target >= 1.2 for thrice-weekly HD.
Urea Reduction Ratio (URR)
Percentage reduction in BUN. Target >= 65%.
Equilibrated Kt/V
Rate-adjusted Kt/V accounting for urea rebound.
Adequacy Met (1=Yes, 0=No)
Whether spKt/V meets KDOQI minimum of 1.2.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Pre-Dialysis BUN (mg/dL) = 60, Post-Dialysis BUN (mg/dL) = 20, Session Duration (hours) = 4, Ultrafiltration Volume (L) = 2.5 = 5 input(s) provided
  2. Calculate Single-Pool Kt/V
    Single-Pool Kt/V = -ln(R - 0.008 * sessionTime) + (4 - 3.5 * R) * (ultrafiltration / postWeight)
    1.301 = 1.301
  3. Calculate Urea Reduction Ratio
    Urea Reduction Ratio = (1 - R) * 100
    66.7 = 66.7
  4. Calculate Equilibrated Kt/V
    Equilibrated Kt/V = spKtV - 0.6 * (spKtV / sessionTime) + 0.03
    1.136 = 1.136

Engine last updated . Checked against 1 independently-derived test — how we verify calculators.

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