When using the new cut-offs fewer false positives for cannabinoids and opiates were seen when using oral fluid screening, while more false positives could be observed for cocaine and amphetamines.
When enforcing DUID legislation, false positive screening results have to be avoided, since (in Belgium) VX689 positive screening test results immediately in a driving ban of 12 h for the DUID suspected driver, even when the confirmation analysis states negative, leading to unnecessary financial consequences for the judicial authorities. The comparison of the two legal approaches demonstrates that the percentage of false positive screening results has decreased since the introduction of the new legislation, i.e. a fast and limited field sobriety test followed by an oral fluid screening and the lowering of the cut-offs for confirmation in plasma. The percentage of plasma samples of tested drivers, in which none of the positive screened target drugs were present in a concentration above the legal cut-off value, has decreased from 17% to 8% since the introduction of the current legislation.