[Kinetic assay of creatinine with the Gemsaec-Fast-Analyzer; comparison with the Fuller's earth method (author's...

A kinetic method is described for the determination of creatinine in serum. The method is adapted for use with Gemsaec-Fast-Analyzer. The reliability criteria of the method are reported. The only interfering substance is bilirubin, which, when present in elevated concentrations, causes an apparent decrease in the level of creatinine. This interference can be avoided by treating the sample with Fuller's earth prior to the creatinine determination. 72 sera were analysed by the kinetic method and by the Fuller's earth method without deproteinization (5). There was excellent agreement between the two methods (y=1.011 x--0.8222;r=0.9970).