Hemodialysis is a life-sustaining procedure for the treatment of patients with end-stage renal disease. A Hemodialysis dose is worked out for patients by comparing the levels of waste such as urea or creatinine in the patient's blood.

Urea Reduction Ratio is a way of comparing urea levels in the blood before and after dialysis.

The formula used is:

URR = [1 - (UPostHD / UPreHD)]

Where
UPreHD = Urea pre Hemodialysis
UPostHD = Urea post Hemodialysis
URR = Urea Reduction Ratio

^* Note units must match to be either mg/dL or mmol/L for both the urea pre and post dialysis.

This information helps interpreting adjustments to be made for future Hemodialysis sessions.

Interpretation:

Urea Reduction Ratio should be >0.65 per session.

References:

• Owen WF, Lew NL, Liu Y, et al. The urea reduction ratio and serum albumin concentration as predictors of mortality in patients undergoing hemodialysis. N Engl J Med. 1993;329(14):1001-6.
• Daugirdas JT. Second generation logarithmic estimates of single-pool variable volume Kt/V: an analysis of error. J Am Soc Nephrol. 1993;4(5):1205-13.