title: An empirical study on the selection of analytes and corresponding cutoffs for immunoassay and GC-MS in a two-step test strategy--buprenorphine example.
abstract: (i) Standard solutions of buprenorphine (B) and three metabolites; (ii) immunoassay (IA) reagents designed for the analysis of B and/or its metabolites; and (iii) clinical urine specimens collected from patients (under B-treatment), constitute the B-System for fundamental study of parameters critical to the two-step test strategy, an analytical approach designed for a high-volume testing environment. The cross-reacting characteristics of IA reagents were examined using standard solutions of B and its metabolites. Resulting data were used as the basis for selecting target analytes suitable for the preliminary and the confirmatory test steps. Test data derived from IA and GC-MS analysis of clinical urine specimens (with natural distribution of B and its metabolites) were quantitatively correlated. Correlation parameters were examined: (i) to verify whether the analyte-pair targeted by the IA and GC-MS test steps has been properly selected; and (ii) to decide on appropriate cutoffs for the two test steps. In conclusion, this study has demonstrated that the most effective analyte(s) that should be targeted in the GC-MS determination step vary with the IA selected in the preliminary test step. All analytes that generate significant responses to the IA reagent should be targeted in the GC-MS test step.
authors.affiliation: Department of Medical Technology, Fooyin University, 151 Ching-Hsueh Road, Ta-Liao Hsiang, Kaohsiung Hsien, 831-02, Taiwan.
authors.forename: Meng-Yan
authors.initials: MY
authors.lastname: Wu
authors.forename: Yu-Shan
authors.initials: YS
authors.lastname: Wang
authors.forename: Ching-Chiang
authors.initials: CC
authors.lastname: Lin
authors.forename: Dong-Liang
authors.initials: DL
authors.lastname: Lin
authors.forename: Lien-Wen
authors.initials: LW
authors.lastname: Su
authors.forename: Mei-Han
authors.initials: MH
authors.lastname: Huang
authors.forename: Ray H
authors.initials: RH
authors.lastname: Liu
mesh_terms: D002047:Buprenorphine / Q000378:metabolism / Q000652:urine*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods* / Q000592:standards; D006801:Humans; D007118:Immunoassay / Q000379:methods*
chemical_list: D002047:Buprenorphine