[Substance abuse analysis of biological materials]

Requests are increasing for biomedical analyses of abused drugs in forensic toxicology, tests at work, testing of drug addicts during rehabilitation, and in therapeutic and other situations. Special guidelines have been prepared in forensic toxicology, with regard to the legal background, information on any sanctions in the event of positive test results, chains of custody for handling samples, analytical methods with known specificity and sensitivity, and interpretation of results based on information of legal drug use. These guidelines should also be recommended in other cases if the results might lead to negative sanctions for the individuals involved. False positive test results have been recorded from cases analysed at local laboratories which had not established the recommended guidelines. The most critical point appears to be the confirmation of positive screening results using specific methods.