What is the recommended Kt/V (kidney dialysis dose) value for patients undergoing hemodialysis (HD) and peritoneal dialysis (PD)?

Kt/V Targets in Dialysis

Hemodialysis (HD)

For patients on thrice-weekly hemodialysis, the target single-pool Kt/V (spKt/V) should be 1.4 per session, with a minimum acceptable dose of 1.2 per session. 1, 2

Standard Dosing Parameters

• Minimum dose: spKt/V of 1.2 per dialysis session for patients dialyzed 3 times weekly 1, 2
• Target dose: spKt/V of 1.4 per dialysis session (or URR of 70%) 1, 2
• The target is set 15% higher than the minimum because of measurement variability, ensuring 95% confidence that delivered dose remains above 1.2 1

Patients with Residual Kidney Function (RKF)

• For patients with residual kidney urea clearance (Kr) greater than 2 mL/min/1.73 m², the minimum spKt/V target can be reduced to as low as 60% of standard targets, depending on dialysis frequency 1
• Twice-weekly HD is NOT appropriate for patients with Kr less than 2 mL/min/1.73 m² 1
• When reducing dialysis dose due to substantial RKF, Kr must be monitored at least quarterly 1

Special Populations Requiring Higher Doses

• Women of any body size should be considered for increased dialysis dose, as Kt/V underestimates adequacy in females 1
• Smaller patients (anthropometric or modeled V ≤25 L) require consideration for dose increase 1
• Malnourished patients (weight <90% of standard body weight or recent unplanned weight loss) should receive increased dose and/or more frequent dialysis 1

Membrane Selection

• High-flux membranes should be used when good dialysate water quality is available, defined as providing β2-microglobulin clearance ≥20 mL/min under actual use conditions 1

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Peritoneal Dialysis (PD)

For peritoneal dialysis patients, the minimum delivered dose should be a total (peritoneal plus residual kidney) Kt/V of 1.7 per week. 1, 2

Patients WITH Residual Kidney Function

• Minimum total Kt/V: 1.7 per week (combined peritoneal and kidney clearance) 1
• Total solute clearance must be measured within the first month after initiating dialysis and at least every 4 months thereafter 1, 2
• If residual urine volume >100 mL/day and residual kidney clearance is counted toward the total weekly goal, obtain 24-hour urine collection for volume and solute clearance at minimum every 2 months 1
• This frequent monitoring is critical because residual kidney function declines at approximately 1 L/week/1.73 m²/month (0.1 mL/min/month), and patients can rapidly fall below minimum targets 1

Patients WITHOUT Residual Kidney Function (Anuric)

• Minimum peritoneal Kt/V: 1.7 per week for patients with urine volume <100 mL/day 1
• Measure peritoneal Kt/V within the first month of starting dialysis and at least every 4 months thereafter 1
• The ADEMEX trial demonstrated no survival benefit from higher peritoneal clearances (2.13 vs 1.62) in anuric patients, supporting the lower target 1

Rationale for Revised Targets

The 2006 guidelines reduced the minimum target from the previous 2.0 to 1.7 per week based on two key randomized controlled trials 1:

• ADEMEX Study: Showed identical survival between groups with peritoneal Kt/V of 1.62 versus 2.13, indicating no benefit from higher small-molecule peritoneal clearance 1
• Hong Kong Study: Demonstrated no survival difference with total Kt/V as low as 1.5-1.7 in patients with minimal residual function 1
• Reanalysis of the CANUSA study revealed that residual kidney function, not peritoneal clearance, was the primary predictor of survival 1

Critical Caveat on Adherence

This minimum target of 1.7 should NOT be interpreted as an average program value—each individual patient must achieve 1.7 or higher. 1 Close attention must be paid to patient adherence with the prescription, as the lower target increases risk if exchanges are missed 1. Assessment of adherence should include talking to patients and evaluating supply consumption 1.

Initiation of Dialysis

• Dialysis should be initiated when residual kidney Kt/V falls below 2.0 per week (approximating kidney creatinine clearance of 9-14 mL/min/1.73 m²) 1
• Definite indications for initiation include: protein-energy malnutrition despite optimization attempts, >6% involuntary weight loss in <6 months, serum albumin decline ≥0.3 g/dL to <4.0 g/dL, or uremic symptoms 1