Reliability of 51Cr-EDTA plasma and urinary clearance as a measure of residual renal function in dialysis patients

AbstractPurpose: In dialysis patients, longer survival is associated with a higher residual renal function. Randomized controlled trials are conducted to clarify how residual renal function can be preserved. However, existing methods for measuring residual renal function are uncertain and there is a need for establishing a standard for measurements of glomerular filtration rate (GFR) in dialysis patients. Methods: 51Cr-EDTA clearances in plasma, urine, and dialysate were evaluated in a sample of 12 hemodialysis and 12 peritoneal dialysis patients. The patients’ condition was generally stable, and all patients were investigated twice within 4–10 days. Results: Plasma clearances of 51Cr-EDTA for all patients ranged between 2.1 and 30.8 mL/min/1.73m2, whereas urinary 51Cr-EDTA clearances ranged from 0.7–20.0 mL/min/1.73m2. This difference was statistically significant (p < 0.001). Week-to-week reproducibility expressed as coefficients of variation were below or equal to 10% for plasma clearances and 13% for ...