Evaluation of three clinical chemical routine methods for the determination of serum uric acid, by mass fragmentography.

A mass fragmentographic method for assay of serum uric acid was developed and used as a reference method to evaluate the accuracy of different routine methods used in clinical chemistry. [1,3-15N2]Uric acid was added to the serum sample and the mixture was subjected to ion-exchange chromatography. After conversion to the tetra-trimethylsilyl derivative the purified mixture was analyzed by combined gas chromatography-mass spectrometry using a multiple ion detector. Within-series imprecision of the reference method as calculated by means of relative standard deviation was 0.6%. The small difference between calculated and found value obtained in different recovery experiments could be explained by this degree of imprecision. In a comparison between results obtained with the reference method and different routine methods, a significant difference was observed only when using an uricase-oxygen consumption method.