The need for confirmation of positive results is now widely accepted but it may be equally important to confirm unexpected negative results. Failure to detect the presence of maintenance drugs may lead to the patient being discharged from a drug treatment clinic and, if attendance at the clinic is one of the terms of continued employment, to dismissal. It seems likely that increasing abuse of drugs and the efforts of regulatory authorities to control this, will lead to the manufacture of more designer drugs. Looking to the future, laboratories will need to ensure that they can detect and quantitate an ever-increasing number of drugs and related substances. The question of confidence in results of drugs of abuse testing raised in 1993 by Watson has assumed even greater importance as a result of attention focused on the OJ Simpson trial in Los Angeles.
Toxicological investigations are likely to be challenged more frequently in the future.
Even if analyses have been performed by GC-MS, there is a need to establish the level of match between the spectrum of the unknown substance and a library spectrum which is considered acceptable for legal purposes. It will also be essential to ensure that computer libraries contain spectra for all substances likely to be encountered in drugs of abuse screening.