Analytical approaches of European Union laboratories to drugs of abuse analysis Roser Badia, Rafael de la Torre,* Sergio Corcione, and Jordi Segura We report a survey on urine drug testing within a total of 269 laboratories of the European Union. Clinical laboratories predominated over forensic laboratories (59.5% vs 28.5%). Screening without identification/ quantification was the common approach used by clin- ical laboratories, whereas screening with identification/ quantification was the approach used by almost all forensic laboratories. Screening was primarily per- formed by immunoassay in both types of laboratories. Gas chromatography coupled to mass spectrometry was the main analytical method used for specific identifica- tion/quantification of drugs, but other methods (includ- ing immunoassays) were also used. Cutoff values ap- plied varied by laboratory type, country, and method used. A high percentage of laboratories did not use or report cutoff values. Overall, countries of the European Union vary significantly in regards to drugs tested, analytical approach, and screening and identification cutoff values. It is recommended to clearly state the analytical method and the cutoff values used when reporting results for drugs of abuse testing. Countries in the European Union (EU) 1 differ in their approaches to the drugs of abuse problem; consequently, there are differences concerning drugs of abuse testing. The development of an internal single market in the EU and the associated free exchange of laboratory services bring new relevance to intercomparison of data. Since 1993, free circulation of workers in the EU has added a further need for harmonized criteria in workplace drug testing. The analytical strategy used for drug testing may depend to a great extent to potential consequences of results. In general terms, analysis of body fluids for drugs of abuse takes place in two different environments: the clinical setting (therapeutic care of drug addicts) and the penalty setting (e.g., forensic medicine, prisons, work- place, insurance, driving, sports). In clinical practice, the analytical result is only one of a series of factors that affect the decision-making process and must be assessed as a complement to the patient–physician relationship. By contrast, in the penalty model, sanctions against the individual providing the specimen are mostly based on analytical results; the reliability of these results, therefore, is essential. Important aspects of urine drug testing include the analytical approach, the methods used, and the cutoff concentrations applied. Usually a two-step procedure is followed in drugs of abuse testing, i.e., a preliminary screening of groups of substances (e.g., opiates), and the identification of specific substances (e.g., morphine, co- deine, 6-acetylmorphine), sometimes accompanied by their quantification. However, given the lack of specific guidelines, different analytical strategies may be consid- ered acceptable by different EU analysts. In this context, in 1993 and 1994 a survey was under- taken in the European Community to examine the reli- ability of urine drug testing. The survey was supported both by the DG V/F/1 (Directorate General V, Employ- ment, Industrial Relations and Social Affairs, Public Health and Safety at Work) of the European Commission and by the Institut Municipal d’Investigacio ´ Me `dica, Barcelona, Spain. The purpose of the study was not only to assess the quality of analysis performed (1), but also to gain insight into the analytical strategies applied in the different European countries and laboratories involved in drugs of abuse testing. Materials and Methods In the 1993 and 1994 survey among laboratories of the EU member states performing drugs of abuse analyses, six test samples of sterile urine containing several drugs and (or) their metabolites were provided for analysis under routine conditions. The drug menu by class of substances Drug Abuse Research Unit, Institut Municipal d’Investigacio ´ Me `dica (IMIM), Autonomous University of Barcelona, Doctor Aiguader 80, E-08003 Barcelona, Spain. *Author for correspondence. Fax 34-3-2213237; e-mail rtorre@imim.es. 1 Nonstandard abbreviations: EU, European Union; EDDP, 1,5-dimethyl- 3,3-diphenyl-2-ethylidiene-pyrrolidine; EIA, enzyme immunoassay; FPIA, flu- orescence polarization immunoassay; TLC, thin-layer chromatography; GC/ MS, gas chromatography–mass spectrometry; and SAMHSA, Substance Abuse and Mental Health Services Administration. Received May 16, 1997; revision accepted November 17, 1997. Clinical Chemistry 44:4 790 –799 (1998) Drug Monitoring and Toxicology 790