Evaluation of buprenorphine CEDIA assay versus GC-MS and ELISA using urine samples from patients in substitution treatment

As buprenorphine becomes more clinically used in heroin substitution treatment, there is an increasing need for methods suitable for high-volume screening. In this study, a new immunochemical test based on CEDIA technology was evaluated for the use in clinical urine drug testing. The method was compared with an existing ELISA method and a gas chromatography-mass spectrometry (GC-MS) method on urine specimens from patients in heroin substitution treatment. The precision of the CEDIA assay was < 9% both within- and between-day at levels at and above the cutoff limit of 5 μg/L. The concordance in qualitative results with an existing ELISA method was 96.8%. The CEDIA measuring range was extended by diluting urine samples 100-fold with saline, and the results agreed well (slope of regression line was 1.09, r 2 = 0.968) with GC-MS. The sensitivity of CEDIA in detecting authentic specimen containing buprenorphine at levels 5 μg/L was 99.5%. Cross-reactivity causing false-positive response was discovered in patients receiving prescribed dihydrocodeine. The urine concentration of total buprenorphine in urine from patients prescribed daily doses between 0.2 and 24 mg ranged from 0.5 to 2900 μg/L. The concentration of the metabolite norbuprenorphine was usually higher, and the median ratio of buprenorphine to norbuprenorphine was 0.23 (95% were below 1). We conclude that the CEDIA assay is suitable for application in high-volume screening of buprenorphine for urine drug testing.