Why Care About Kt/V?

  • Urea is considered a surrogate to other small molecular weight uremic toxins and is easy to measure in the blood pre and post hemodialysis.
  • Although its use has limitations, it is an easily measured and useful marker of hemodialysis adequacy.
  • Kt/Vurea has helped standardize dialysis dosage based on urea clearance. It provides a tool to avoid grossly inadequate dialysis.
  • Its routine monitoring may help to identify problems of dialysis delivery such as access recirculation. 
  • Urea reduction ratio (URR= 1-postdialysis BUN/predialysis BUN) is a less optimal measure of dialysis adequacy as it does not account for ultrafiltration during dialysis and assumes that V is constant during dialysis.