The estimation, measurement, and relevance of the glomerular filtration rate in stage 5 chronic kidney disease.

The glomerular filtration rate (GFR) is considered the best index of overall kidney function. The level of GFR is used in patients with chronic kidney disease (CKD) to classify them into CKD stages. Stage 5 CKD encompasses patients with a GFR below 15 ml/minute/1.73 m(2) and those requiring chronic dialysis. Preservation of GFR, even at its very low level, is of great importance in both dialysis and non-dialysis stage 5 CKD patients. Residual GFR is considered in the prescription of both hemodialysis and peritoneal dialysis and interventions to preserve residual GFR are an active area of clinical research. The application of traditional methods of estimating and measuring GFR can be problematic in this patient population. This review will focus on the methods available to quantify GFR in stage 5 CKD and their use in both clinical and research settings.