For many years, urine has been the preferred specimen for drug of abuse testing. Depending on the substance or metabolite tested, the type of consumption (smoking, sniffing, injection), the dose and the frequency of consumption, drugs can be measured for several days or weeks. In some cases (chronic abuse of cannabis or benzodiazepines) the substances are detectable in urine for several weeks after the last intake. For a control of abstinence, urine collection should take place within 24 hours of summons. Samples then are collected under direct supervision to minimize manipulation attempts.
Depending on the proposed question the following substances and substance classes can be analyzed in urine:
- Prescription drugs (see also Therapeutic Drug Monitoring)