SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

A48
MULTICENTER EV ALUA TION OF THE ROCHE ONLINE® TDM CARBAZEPINE ASSA Y FOR
ROCHEIHITACHI ANALYZER SYSTEMS
Mary Jane Coffing* I, Roger L. Bertholf, Martin Kroll 3 , Hilmar H. Luthe 4 , Alain Verstraete 5, Heike
Sauter 6 , RaifRoeddiger 6
IClinical Trials, Roche Diagnostics Cooperation, Indianapolis, IN, USA; 2University of Florida Health
Science Center, Jacksonville, FL, USA; 3Dallas VA Medical Center, Dallas, TX, USA; 4Department
Clinical Chemistry, Universitiit G6ttingen, Germany; 5Ghent University Hospital, Ghent, Belgium;
6Clinical Trials, Roche Diagnostics GmbH, Mannheim, Germany
Carbamazepine is an anticonvulsant and anti-manic drug, used in the treatment of trigeminal neuralgia,
bipolar disorders, epilepsy, and a wide variety of seizure disorders. Monitoring carbamazepine
concentrations is essential during therapy in order to ensure achievement of optimal therapeutic effect,
while avoiding the impact of both subtherapeutic and toxic drug levels.
The analytical performance of a new, Roche homogeneous microparticle immunoassay for Carbamazepine
was evaluated at four sites two in Europe and two in the Unites States. Intra- and interassay imprecision,
lower detection limit, control recovery, and linearity were assessed. Further, the assay method was compared
to the CEDIA Carbamazepine assay on RochelHitachi 917 and MODULAR P analyzers, Abbott FPIA
Carbamazepine assay on the Abbott AxSYM and TDx analyzers, and the Roche FP assay on INTEGRA 800.
Serum vs. sodium heparin plasma comparison was also performed.
OnLine Carbamazepine intra-assay imprecision showed 8Ds sO.14 J..lg/mL for concentrations up to 4
J..lg/mL and CVs s3.4 for concentrations >4 J..lg/mL. Interassay imprecision showed SDs s0.15 J..lglmL for
concentrations up to 4 J..lglmL and CVs s4.1 for concentrations >4 J..lglmL. Analytical sensitivity (lower
detection limit) to 0.22 J.lglmL and linearity to the 20.0 J..lglmL were observed. Roche COBAS FP control
materials recovered within range at all sites and competitor control materials recovered within
manufacturers' ranges with one exception.
PassinglBablok regression analysis was used to assess method comparison. All comparisons demonstrated
c I ose agreement between competitive met h 0 d s as note d'mthetable b eow: I
Methodoiogyllnstrument
N Slope Intercept Correlation
x
y
Coefficient
Site 1 CEDIA MODP OnLine MOD P 168 1.055 -0.248 0.993
8ite2 CEDIA 917-R OnLine 917-R 157 0.982 0.093 0.983
Site 3 CEDIA MODP OnLine MODP 161 1.059 -0.642 0.972
COBASFP OnLineMODP 161 1.121 -0.458 0.984
INTEGRA 800
Abbott AxSYM I OnLine MOD P 161 1.120 -0.426 0.975
Site 4 CEDIA 917 OnLine 917 145 1.039 -0.409 0.988
Abbott TDx OnLine 917 145 1.068 -0.111 0.986
Comparison of serum vs. sodium heparin plasma produced this regression equation: y 1.l07x - 0.074,
r=0.982 (n=47). The OnLine Carbamazepine TDM reagent met or exceeded analytical specifications and
all clinically relevant performance criteria in this evaluation.
Key Words: Carbamazepine, Automated Method, Multicenter Evaluation
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