title: One-sample determination of glomerular filtration rate (GFR) in children. An evaluation based on 75 consecutive patients.
abstract: OBJECTIVE
  From a clinical point of view determination of glomerular filtration rate (clearance) is important. The aim of the present study was to compare the one-sample clearance to reference multiple-sample (51)Cr-EDTA clearance in consecutively referred children suspected of or with established nephro-urological disorders.
  
  
  METHODS
  A total of 75 children, age ½-13 years, received a quantitative intravenous injection of (51)Cr-EDTA followed by six plasma samples 10-120 min after injection. The multiple-sample clearance was measured as injected dose relative to the area under the plasma radioactivity curve. The one-sample clearance was determined from a single plasma sample collected at 60, 90 or 120 min after injection according to the one-pool method.
  
  
  RESULTS
  The overall accuracy of one-sample clearance was excellent with mean numeric difference to the reference value of 0.7-1.7 mL/min. In 64 children, the one-sample clearance was within ± 4 mL/min of the multiple-sample value. However, in 11 children the numeric difference exceeded 4 mL/min (4.4-19.5). Analysis of age, body size, distribution volume, indicator retention time, clearance level, curve fitting, and sampling time could not explain the observed large difference between one-sample and multiple-sample clearance in these 15% of the children.
  
  
  CONCLUSIONS
  In the majority of children there is an excellent agreement between one-sample clearance and multiple-sample clearance. However, unexpectedly in a small fraction (15%) larger discrepancies are found. If an accurate clearance value is essential a multiple-sample determination should be performed.
authors.affiliation: Departments of Clinical Physiology and Nuclear Medicine , Hvidovre.
authors.forename: Ulrik L
authors.initials: UL
authors.lastname: Henriksen
authors.forename: Inge-Lis
authors.initials: IL
authors.lastname: Kanstrup
authors.forename: Jens H
authors.initials: JH
authors.lastname: Henriksen
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002860:Chromium Radioisotopes; D004492:Edetic Acid / Q000493:pharmacokinetics; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007223:Infant; D008297:Male; D008657:Metabolic Clearance Rate; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012016:Reference Values; D014018:Tissue Distribution; D014570:Urologic Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology
chemical_list: D002860:Chromium Radioisotopes; D019275:Radiopharmaceuticals; D004492:Edetic Acid