Cavalier Etienne, Rozet Eric, Dubois Nathalie, Charlier Corinne, Hubert Philippe, Chapelle Jean-Paul, Krzesinski Jean-Marie, Delanaye Pierre
Department of Clinical Chemistry, University of Liège, CHU Sart-Tilman, B-4000 Liège, Belgium.
Clin Chim Acta. 2008 Oct;396(1-2):80-5. doi: 10.1016/j.cca.2008.07.011. Epub 2008 Jul 18.
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.
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.
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.
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.
