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. Current and previous generation analytical systems used were Architect and AxSym (Abbott Laboratories), cobas c 501 module and COBAS INTEGRA 800 analyzer (Roche Diagnostics GmbH), and Dimension Vista and Dimension Xpand (Siemens Healthcare Diagnostics Inc). Carbamazepine, digoxin, phenobarbital, phenytoin, theophylline, tobramycin, vancomycin, and valproic acid were measured using leftover routine samples. RESULTS: Good performance and comparability of the drug assays was seen on all systems for carbamazepine, phenytoin, and valproic acid except for phenytoin on the Dimension Vista. Deviations from the acceptance criteria were found with digoxin, phenobarbital, theophylline, tobramycin, and vancomycin. Despite a change of the analytical principle on the Roche systems for most drugs, the results demonstrated a very good between-system comparability of the concentration measured. Systematic deviations were found between AxSYM and ARCHITECT for digoxin, phenobarbital, and tobramycin, and between Dimension Xpand and Dimension Vista for digoxin and vancomycin. CONCLUSIONS: The study revealed differences between assays, platforms, and assay principles. Care should be taken if methods or instruments are replaced in a laboratory. Laboratories are advised to perform their own method comparison studies and to inform their customers about the effect on the therapeutic ranges in case of observed clinically significant deviations.
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. Current and previous generation analytical systems used were Architect and AxSym (Abbott Laboratories), cobas c 501 module and COBAS INTEGRA 800 analyzer (Roche Diagnostics GmbH), and Dimension Vista and Dimension Xpand (Siemens Healthcare Diagnostics Inc). Carbamazepine, digoxin, phenobarbital, phenytoin, theophylline, tobramycin, vancomycin, and valproic acid were measured using leftover routine samples. RESULTS: Good performance and comparability of the drug assays was seen on all systems for carbamazepine, phenytoin, and valproic acid except for phenytoin on the Dimension Vista. Deviations from the acceptance criteria were found with digoxin, phenobarbital, theophylline, tobramycin, and vancomycin. Despite a change of the analytical principle on the Roche systems for most drugs, the results demonstrated a very good between-system comparability of the concentration measured. Systematic deviations were found between AxSYM and ARCHITECT for digoxin, phenobarbital, and tobramycin, and between Dimension Xpand and Dimension Vista for digoxin and vancomycin. CONCLUSIONS: The study revealed differences between assays, platforms, and assay principles. Care should be taken if methods or instruments are replaced in a laboratory. Laboratories are advised to perform their own method comparison studies and to inform their customers about the effect on the therapeutic ranges in case of observed clinically significant deviations.
Authors: Janko Samardzic; Anne Smits; Isabel Spriet; Ivan Soldatovic; Andrew Atkinson; Milica Bajcetic; John N Van Den Anker; Karel Allegaert Journal: Biomed Res Int Date: 2016-08-21 Impact factor: 3.411
Authors: Kristian H Mikkelsen; Morten Frost; Martin I Bahl; Tine R Licht; Ulrich S Jensen; Jacob Rosenberg; Oluf Pedersen; Torben Hansen; Jens F Rehfeld; Jens J Holst; Tina Vilsbøll; Filip K Knop Journal: PLoS One Date: 2015-11-12 Impact factor: 3.240
Authors: C J Hodiamont; N P Juffermans; S E Berends; D J van Vessem; N Hakkens; R A A Mathôt; M D de Jong; R M van Hest Journal: J Antimicrob Chemother Date: 2021-10-11 Impact factor: 5.790