Comparability and imprecision of 8 frequently used commercially available immunoassays for therapeutic drug monitoring.

Background: The development of new immunoassays for therapeutic drug monitoring and the adaptation of current assays on new analytical platforms has led to a plethora of different tests. This variability may influence comparability between the methods and affect interpretation of test results used for guiding drug treatment.

Methods: Comparability and imprecision of 8 immunoassays for therapeutic drug monitoring were evaluated using 6 different analyzers from 3 manufacturers.