Enzyme immunoassay validation for the detection of buprenorphine in urine.
A solid-phase enzyme immunoassay involving microtiter plates was proposed by Microgenics to screen buprenorphine in urine. The intra-assay precision at 10 ng/mL was 7.7% (coefficient of variation). The immunoassay was determined to have no cross-reactivity with codeine, dihydrocodeine, morphine, ethylmorphine, 6-monoacetylmorphine, methadone, pholcodine, propoxyphene, dextromoramide, and dextromethorphan at 1 and 10 mg/L. A low cross-reactivity (3% at 1 ng/mL) was observed at low concentrations of norbuprenorphine. After comparing this new immunological test (Singlestep ELISA) for 76 urine specimens with our validated high-performance liquid chromatography-electrospray mass spectrometry (HPLC-ES-MS) procedure, an optimum cutoff concentration of 2 ng/mL was determined for the kit. At this cutoff, the screening assay was able to determine more than 90% of true results with 43.4% true positives and 48.7% true negatives. Four positive urines (5.3%) were not confirmed by HPLC-ES-MS. In only one case, the negative urine test was confirmed as positive by HPLC-ES-MS (buprenorphine: 62.5 ng/mL). Buprenorphine concentrations determined by HPLC-ES-MS ranged from 1.2 to 1052 ng/mL. Of the four potential adulterants (hypochloride 50 mL/L, sodium nitrite 50 g/L, liquid soap 50 mL/L, and sodium chloride 50 g/L) that might be added to a positive urine specimen, none were able to cause a false-negative response by the immunoassay. The results of this study support the concept that the Singlestep ELISA for buprenorphine determination in urine should be considered as a new, valided screening procedure.
Cirimele
V
V
Institut de Médecine Légale, Laboratoire de Toxicologie, 11, rue Humann, 67085 Strasbourg, France. vincent.cirimele@medecine.u-strasbg.fr
Kintz
P
P
Lohner
S
S
Ludes
B
B
D002047:Buprenorphine / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D005554:Forensic Medicine; D006801:Humans; D009294:Narcotics / Q000652:urine*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization; D015813:Substance Abuse Detection / Q000379:methods*
D009294:Narcotics; D002047:Buprenorphine