If you are on dialysis, you will want to know how well your dialysis is cleaning your blood.
Dialysis Basics > Dialysis Adequacy Labs
Every month your care team will take some blood from your bloodlines and send it to the lab. This lab test measures your Blood Urea Nitrogen (BUN). This test gives us two measurements, the URR and the Kt/V.
Urea Reduction Ratio (URR):
Once every month, your dialysis care team will take a tube of blood right as you start dialysis.
They will also take a tube of blood at the end of your dialysis treatment.
The two levels are compared and you are given a URR number.
This number tells you how well the dialysis cleaned your blood for that treatment only.
Your URR level should be at least 70%. The higher your number is, the better your blood is cleaned.
Sometimes your doctor will increase the length of time of your treatment so your blood can get cleaner.
URR is easy to calculate. But it does not take body weight into account.
It also does not take into account the amount of time it takes to remove fluid during your treatment.
A more precise measure of hemodialysis adequacy is call Kt/V.
Kt/V:
Kt/V (kay-tee-over-vee) stands for:
K = dialyzer clearance in mL/min
t = length of the dialysis treatment in minutes (time)
V = volume of water in the body that contains urea (waste products)
To figure out your Kt/V, a BUN level and weight are checked before and after a treatment.
The results are put into a formula. Your goal for Kt/V is greater than 1.4%.
Higher is better, so the more time you are on dialysis, the better your Kt/V will be.
These labs are often difficult to understand.
You can ask your doctor or your nurse any questions you have about your URR or your Kt/V.