title: Performance of iohexol determination in serum and urine by HPLC: validation, risk and uncertainty assessment.
abstract: BACKGROUND
  Determination of glomerular filtration rate plays an important role in nephrological practice. Iohexol is a reference marker for glomerular filtration rate determination. It is available and safe. The aim of this study was to develop a simple, efficient and easy to use analytical method for the quantification of iohexol in serum and urine by high performance liquid chromatography and to thoroughly validate this method.
  
  
  METHODS
  The HPLC method was inspired from the method published by Krutzen. The e.noval software V2.0 (Arlenda, Liège, Belgium) was used to compute all validation results.
  
  
  RESULTS
  The validation results indicate that the method will give accurate and reliable results for serum values ranging from 12.95 to 1295 microg/ml and for urine values ranging from 86.0 to 4144 microg/ml. In routine practice, iohexol concentrations found in plasma after injection range from 40 to 600 microg/ml. The expected urinary values are much wider. One should not hesitate to dilute urine samples to fit with the validated range over 5000 microg/ml.
  
  
  CONCLUSIONS
  This is the first time that a reference method for the determination of GFR is validated with such a rigorous and thorough protocol. Contrary to other GFR markers, iohexol is now strongly validated from an analytical point of view.
authors.affiliation: Department of Clinical Chemistry, University of Liège, CHU Sart-Tilman, B-4000 Liège, Belgium. Etienne.cavalier@chu.ulg.ac.be
authors.forename: Etienne
authors.initials: E
authors.lastname: Cavalier
authors.forename: Eric
authors.initials: E
authors.lastname: Rozet
authors.forename: Nathalie
authors.initials: N
authors.lastname: Dubois
authors.forename: Corinne
authors.initials: C
authors.lastname: Charlier
authors.forename: Philippe
authors.initials: P
authors.lastname: Hubert
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Chapelle
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Krzesinski
authors.forename: Pierre
authors.initials: P
authors.lastname: Delanaye
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007472:Iohexol / Q000032:analysis* / Q000378:metabolism*; D018570:Risk Assessment; D044967:Serum / Q000737:chemistry; D035501:Uncertainty; D014556:Urine / Q000737:chemistry
chemical_list: D007472:Iohexol