title: Analytical performance evaluation of ADVIA Chemistry Carbamazepine_2 assay: minimal cross-reactivity with carbamazepine 10, 11-epoxide and none with hydroxyzine or cetirizine.
abstract: Carbamazepine is an anticonvulsant requiring routine therapeutic drug monitoring. Recently, Siemens Healthcare Diagnostic Division released a new carbamazepine assay: ADVIA Chemistry Carbamazepine_2 (Carbamazepine_2) for application on ADVIA analyzers. We evaluated the analytical performance of this assay as well as its potential cross-reactivities with carbamazepine 10, 11-epoxide, hydroxyzine, and cetirizine. The within-run and between-run precisions of the Carbamzepine-2 assay were <6% and limit of detection was 0.5 microg/ml using ADVIA 1800 analyzer. The assay was linear up to a carbamazepine concentration of 20.0 microg/ml. The new method compared well with a widely used carbamazepine EMIT 2000 assay on the Hitachi 917 analyzer. Using 75 patients' specimens (where carbamazepine concentrations varied from 0.5 to 21.7 microg/ml) and carbamazepine EMIT 2000 as the reference method (x-axis), we observed the following regression equation: y=1.04 x+0.32 (r=0.99). The new carbazepine_2 method was not affected by a hemoglobin concentration of 1,000 mg/dl, conjugated or unconjugated bilirubin concentration of 60 mg/dl, and triglyceride concentration of 1,000 mg/dl. In addition, this assay showed no cross-reactivity with hydroxyzine or cetirizine and demonstrated minimal cross-reactivity with carbamazepine 10, 11-epoxide. We conclude that the ADVIA Chemistry carbamazepine_2 assay has adequate precision and accuracy for routine therapeutic drug monitoring of carbamazepine in clinical laboratories.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, Texas, USA. Amitava.Dasgupta@uth.tmc.edu
authors.forename: Amitava
authors.initials: A
authors.lastname: Dasgupta
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Reyes
authors.forename: Barbara G
authors.initials: BG
authors.lastname: Davis
authors.forename: Anne M
authors.initials: AM
authors.lastname: Marlow
authors.forename: Myrtle
authors.initials: M
authors.lastname: Johnson
mesh_terms: D000927:Anticonvulsants / Q000097:blood / Q000737:chemistry; D001774:Blood Chemical Analysis / Q000379:methods*; D002220:Carbamazepine / Q000031:analogs & derivatives* / Q000097:blood / Q000737:chemistry*; D017332:Cetirizine / Q000097:blood / Q000737:chemistry*; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D006919:Hydroxyzine / Q000031:analogs & derivatives / Q000097:blood / Q000737:chemistry*; D007118:Immunoassay / Q000379:methods*; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000927:Anticonvulsants; D006919:Hydroxyzine; D002220:Carbamazepine; C012227:carbamazepine epoxide; D017332:Cetirizine