Validation of a Free Phenytoin Assay on Cobas c501 Analyzer Using Calibrators From Cobas Integra Free Phenytoin Assay by Comparing its Performance With Fluorescence Polarization Immunoassay for Free Phenytoin on the TDx Analyzer

摘要

For many years, fluorescence polarization immunoassay ( ) on the x analyzer has been used for determination of free phenytoin concentration. Recently bbott aboratories decided to discontinue the x analyzer and related assays on this analyzer. Free phenytoin assay is also available from oche iagnostics for application on the obas ntegra analyzer (fluorescence polarization assay) but not on obas c510 analyzer. Free phenytoin calibrators from the obas ntegra free phenytoin assay and the reagents from the phenytoin assay were used for the determination of free phenytoin on the obas c501 analyzer. The intra‐run and inter‐run precisions were both <7.2%. The assay was linear from 0.2 to 4 μg/ml. The free phenytoin assay on the obas c501 was compared with the assay on the x analyzer using sera from 25 patients receiving phenytoin (phenytoin concentration between 0.3 and 3.7 μg/ml). The following regression equation was observed: = 0.9899 + 0.0408 ( = 0.98, = 25). In conclusion, the free phenytoin assay on the obas c501 analyzer is a valid alternative to free phenytoin assay on the x analyzer. J. Clin. Lab. Anal. 27:1–4, 2013. © 2012 Wiley Periodicals, Inc.