title: Total plasma clearance versus urinary plasma clearance of (51)Cr-EDTA in patients with cirrhosis with and without fluid retention.
abstract: OBJECTIVE
  In patients with fluid retention, the total plasma clearance of (51)Cr-EDTA (ClP) may overestimate the glomerular filtration rate (GFR). The present study was therefore undertaken in order to compare ClP with the urinary plasma clearance of (51)Cr-EDTA (ClU) in patients with cirrhosis with and without fluid retention.
  
  
  METHODS
  A total of 136 patients with cirrhosis (24 without fluid retention, 112 with ascites) received a quantitative intravenous injection of (51)Cr-EDTA followed by plasma and quantitative urinary samples for 5 hours. ClP was determined from the injected dose relative to the plasma concentration-time area, extrapolated to infinity. ClU was determined as urinary excretion relative to the plasma concentration-time area up to voiding.
  
  
  RESULTS
  In patients without fluid retention, the difference between ClP and ClU (ClP - ClU = ClΔ) was mean 4.5 mL/min/1.73 m(2). In patients with ascites, ClΔ was significantly higher (17.6 mL/min/1.73 m(2), p < 0.0001). ClΔ increased with lower values of GFR (r = - 0.458, p < 0.001). Repeated measurements of ClU in a subgroup of patients with fluid retention (n = 25) gave almost identical values. Different types of corrections of one-pool clearance were almost identical with ClP, except for higher clearance values, which were somewhat underestimated by the former.
  
  
  CONCLUSIONS
  In patients with fluid retention and ascites ClP and corrected one-pool clearance overestimates GFR substantially. Although ClU may underestimate GFR slightly, patients with ascites should collect urine quantitatively in order to obtain a reliable measurement of GFR.
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, Center for Functional and Diagnostic Imaging and Research, Hvidovre Hospital , Hvidovre , Denmark.
authors.forename: Ulrik L
authors.initials: UL
authors.lastname: Henriksen
authors.forename: Hanne B
authors.initials: HB
authors.lastname: Hansen
authors.forename: Helmer
authors.initials: H
authors.lastname: Ring-Larsen
authors.forename: Flemming
authors.initials: F
authors.lastname: Bendtsen
authors.forename: Jens H
authors.initials: JH
authors.lastname: Henriksen
mesh_terms: D000328:Adult; D000368:Aged; D002860:Chromium Radioisotopes / Q000493:pharmacokinetics*; D004492:Edetic Acid / Q000493:pharmacokinetics*; D005260:Female; D005355:Fibrosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000652:urine*; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011877:Radionuclide Imaging
chemical_list: D002860:Chromium Radioisotopes; D004492:Edetic Acid
keywords: Ascites; corrected one-pool clearance; delayed indicator distribution; glomerular filtration rate; peritoneal clearance