Impact of hemodialysis duration on the removal of uremic retention solutes

Kidney Int. 2008 Mar;73(6):765-70. doi: 10.1038/ Epub 2007 Dec 26.


Several studies have stressed the importance of dialysis time in the removal of uremic retention solutes. To further investigate this, nine stable chronic hemodialysis patients were dialyzed for 4, 6, or 8 h processing the same total blood and dialysate volume by the Genius system and high-flux FX80 dialyzers. Inlet blood and outlet dialysate were analyzed for urea, creatinine, phosphorus, and beta2-microglobulin at various times. Total solute removal, dialyzer extraction ratios, and total cleared volumes were significantly larger during prolonged dialysis for urea, creatinine, phosphorus, and beta2-microglobulin. Reduction ratios increased progressively, except for phosphate and beta2-microglobulin, where the ratios remained constant after 2 h. In contrast, no significant difference was found for the reduction ratios of all solutes and Kt/V(urea) between the three different sessions. With longer dialyses, solutes are efficiently removed from the deeper compartments of the patient's body. Our study shows that care must be taken when using Kt/Vurea or reduction ratios as the only parameters to quantify dialysis adequacy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Humans
  • Male
  • Middle Aged
  • Renal Dialysis / standards*
  • Time Factors
  • Uremia / therapy*
  • Urine / chemistry*