[Analysis of tools, methods and results of toxicological screening for detection of drug abuse in Italian professional drivers]

Background:Three years after a protocol agreement between the State and the Regions came into force in 2008 (drug testing at the workplace Law) a large number of studies have been conducted to analyse and test the efficacy of on-site screening tests for detection of drug consumption (opiates, cocaine, cannabinoids, amphetamine and methamphetamine, MDMA and methadone), which are frequently used by the occupational health physician, and also to present data resulting from workplace drug testing obtained during health surveillance programmes. The aim of the present study was to verify whether the features of sensitivity and specificity of the most common on-site testing ensure correct application of the provisions of current Italian legislation and also to analyse published studies showing the frequency of positive drug testing.

Methods:A review of Italian and international literature was carried out aimed at identifying studies relating to: (1) performance of on-site screening tests frequently used by the occupational health physician, (2) prevalence of drug use/abuse among Italian public and commercial transport drivers. A comparison between the studies was then carried out.

Results:Several rapid on-site screening tests are commercially available (Italian law does not provide standards for the technical specifications of the tests), the sensitivity and specificity of which varies depending on the model and the substance tested. The sensitivity of these tools is poor when used for the detection of low concentrations of drugs and/or their metabolites in urine (close to the cut-off). Studies are lacking that compare on-site tests performed by the occupational health physician and confirmative tests in specialized laboratories (with particular regard to false positives found by the occupational health physician). The major studies in terms of methods and/or size reported a positive rate (confirmed at the first level) between 1.6% and 1.9%. The drugs most frequently used/abused were cannabis and cocaine.

Conclusions:The performance of on-site screening tests (to detect psychotropic substances on urine matrix) and the methodology required by Italian law show that the aims of Italian workplace drug testing legislation have not been achieved The low positive rate observed in Italian studies could be due to an error in the first phase of screening performed by the occupational health physician.