Experiences in drug screening by police officers with DrugWipe II and chemical-toxicological analysis of blood samples

In the samples pre-tested with DrugWipe(registered trademark)II, cannabinoids could be detected in 56.6 % of cases, amphetamines in 29.8 %, opiates in 15.8 % and cocaine/benzoylecgonin in 14.5 %. Unexpectedly high, however, was the per-centage of blood samples (14.2 %) that were shown to contain no drugs and/or their metabolites despite positive pretests. However, the results for the opiate subgroup indicated that DrugWipe(registered trademark)II could be a suitable test for drug screening. As a pre-test to detect consumption of opiates it is no worse than a (rapid) urine test or an Inspec(registered trademark) blood test. Nonetheless DrugWipe(registered trademark)II is neither sensitive nor specific enough in testing for cocaine, amphetamines or cannabis in order to be used on-site by police. Amongst the amphetamines only the methylendioxyamphetamines are detected reliably, while amphetamine is not. On the other hand there were also many false positive DrugWipe(registered trademark)II tests amongst the amphetamines. This also applied to cannabis. One reason - apart from non specific reactions - could be passive consumption. The results of the investigations presented here seem to suggest that there is no sound scientific basis for restricting investigation requests to the parameters suggested as positive by pre-tests. Neither sensitivity nor specificity of DrugWipe(registered trademark)II is good enough to be the only basis of such limited and specific analysis.