Article original Évaluation du dépistage de quatre classes de stupéfiants et des benzodiazépines dans le sang total laqué par l'analyseur Evidence Investigator r

analyser has been evaluated in this study. 128 forensic blood samples known to be positive for at least one of these classes by chromatography coupled to mass spectrometric detection were analysed. Results and discussion: Speci- ficity was 79.0% for amphetamines, 98.1% for cannabinoids, and 100% for opiates, cocaine, and benzodiazepines. Sensitivity was 33.3% for amphetamines, 78.4% for benzodiazepines, 93.2% for cannabinoids, 93.5% for opiates and 95.2% for cocaine. 3.9% of false negatives were observed all classes taken together, due to low concentrations of ana- lytes or due to a bad recognition of some analytes by antibodies. The 4.0% of false positive results were predominantly observed during amphetamines detection, probably due to presence of biogen amines, as it has previously been re- ported. An improvement of the technique has been carried out by adding a supplementary wash step during sample preparation. An optimisation of cutoff levels is possible to reduce false negative results during benzodiazepines and cannabinoids detection. Conclusion: This immunoanalytical method enables an efficient detection of opiates, cocaine, cannabinoids and benzodiazepines in forensic blood samples. However a further confirmation and quantification by mass spectrometry techniques remains necessary.