title: Reliability of ⁵¹Cr-EDTA plasma and urinary clearance as a measure of residual renal function in dialysis patients.
abstract: OBJECTIVE
  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/1.73 m², whereas urinary ⁵¹Cr-EDTA clearances ranged from 0.7-20.0 mL/min/1.73 m². 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 urinary clearances in hemodialysis patients and 14% in peritoneal dialysis patients.
  
  
  CONCLUSIONS
  This study demonstrated a difference between ⁵¹Cr-EDTA plasma and urinary clearances in dialysis patients. Plasma clearance of ⁵¹Cr-EDTA had the best reproducibility. For repeated measurements as in clinical prospective trials, we recommend ⁵¹Cr-EDTA plasma clearance based on blood sampling at 5 + 24 hours with subtraction of ⁵¹Cr-EDTA dialysate clearance in peritoneal dialysis patients. Further studies are needed to corroborate our findings.
authors: Department of Renal Medicine, Aarhus University Hospital, Skejby, Denmark. krista@ki.au.dk
authors: Krista D
authors: KD
authors: Kjaergaard
authors: Jens D
authors: JD
authors: Jensen
authors: Bente
authors: B
authors: Jespersen
authors: Michael
authors: M
authors: Rehling
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002860:Chromium Radioisotopes / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D003404:Creatinine / Q000097:blood / Q000652:urine; D003718:Denmark; D015314:Dialysis Solutions; D004492:Edetic Acid / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000503:physiopathology*; D007674:Kidney Diseases / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology / Q000652:urine; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis; D011446:Prospective Studies; D006435:Renal Dialysis; D015203:Reproducibility of Results
chemical_list: D002860:Chromium Radioisotopes; D015314:Dialysis Solutions; D004492:Edetic Acid; D003404:Creatinine