Analytical approaches of European Union laboratories to drugs of abuse analysis

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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 clinical laboratories, whereas screening with identification/quantification was the approach used by almost all forensic laboratories. Screening was primarily performed by immunoassay in both types of laboratories. Gas chromatography coupled to mass spectrometry was the main analytical method used for specific identification/quantification of drugs, but other methods (including immunoassays) were also used. Cutoff values applied 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.