Screening tossicologico su matrice pilifera: verifica delle prestazioni analitiche secondo lo standard internazionale ISO 15189
Hair drug screening test for illegal drugs: method verification according to ISO 15189 standard

AUTORI

ABSTRACT

Hair drug screening test for illegal drugs: method verification according to ISO 15189 standard

Introduction: hair testing is an alternative matrix for diagnosis and monitoring of drug misuse. The aim of the present study was to evaluate the analytical performances of 7 semi-quantitative immunoassays using hair specimens according to the ISO 15189 standard, in order to introduce hair drug screening in our practice.
Methods: QuantILab DRI Cocaine Metabolite, Opiate, Cannabinoid, Methadone, Amphetamines, Ecstasy and Immunalysis Buprenorphine, were applied on Ilab Taurus (Instrumentation Laboratory SpA, a Werfen Company, Milano). The imprecision verification study consisted in calculating the within-laboratory imprecision (SWL) using positive quality control hair materials, followed by assessment of uniformity with manufacturer’s inter-assay claims and acceptability of test results. A total of 25 EQAS and 29 hair specimens were tested to verify the diagnostic sensitivity (SELAB) and specificity (SPLAB). To confirm the results, an UPLC-MS/MS method accredited according to ISO 15189 standard was used.
Results: SWL obtained for 3 assays were lower than those specified by the manufacturer, opposed to Cannabinoid, Amphetamines, Buprenorphine and Ecstasy assays; thus Upper Verification Limit (UVL) were calculated. SWL for Cannabinoid, Amphetamines and Buprenorphine assays were lower than UVL; Ecstasy assay SWL (8.40%) was greater than UVL (8.39%), but still lower than state-of-the-art imprecision (<15%). SELAB and SPLAB were 100% for all assays except SPLAB for Cannabinoid (95.2%) and Amphetamines (92.9%); 95% confidence intervals of manufacturer diagnostic specificity (SPPROD) were calculated. SPLAB for both assays were included in the 95% CI of SPPROD.
Discussion: for all immunoassays, the verifications were successful and exhibit good diagnostic efficiency for hair drug screening.

BIBLIOGRAFIA