Urea reduction ratio
The urea reduction ratio (URR) is a dimensionless number used to quantify dialysis treatment adequacy. == Definition == U R R = U p r e − U p o s t U p r e × 100 % {\displaystyle URR={\frac {U_{pre}-U_{post}}{U_{pre}}}\times 100\%} Where: Upre is the pre-dialysis urea level Upost is the post-dialysis urea level Whereas the URR is formally defined as the urea reduction "ratio", in practice it is informally multiplied by 100% as shown in the formula above, and expressed as a percent.