Roadside drug testing: comparison of two legal approaches in Belgium

Internationally, urine on-site testing has been used for detecting drivers under the influence of drugs (DUID) but more and more countries, such as Belgium, are switching to oral fluid screening.

To compare the previous (published in 1999) and current (published 2009) enforcement procedures of DUID in Belgium. The two evaluated procedures differ in the way the drivers are screened by the police (signs of impairment versus signs of recent drug use), the matrix for screening (urine versus oral fluid) and the analytical cut-off concentrations in plasma.

Data on positive screening and confirmation results were gathered from 1st April 2008 to 30th September 2010, when urine screening (Dipro Druglab panels test) was performed; and from 1st October 2010 to 31st March 2013, when an on-site oral fluid test (Securetec Drugwipe 5(+)) was used.

Approximately 4100 data sets related to urine screening and 3900 data sets related to oral fluid screening were studied. Eighty-eight percent of positive urine on-site tests yielded positive results in plasma for cannabis, 21% for cocaine, 20% for amphetamines and 7% for opiates. Sixty-six percent of the positive oral fluid on-site tests yielded positive results in plasma for cannabis, 30% for cocaine, 28% for amphetamines and 8% for opiates. For cannabis, opiates and amphetamines more negative results in plasma were observed in the period of urine screening.

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 involving oral fluid screening.