title: A survey of drugs of abuse testing by clinical laboratories in the United Kingdom. Steering Committee for the UK-External Quality Assessment Scheme for Therapeutic Drug Assays.
abstract: An external quality assessment survey of testing facilities in UK clinical laboratories for the detection of drugs of abuse was made with nine freeze-dried samples of urine containing representative drugs with their metabolites from the following seven classes; amphetamines and stimulants, barbiturates, cannabinoids, cocaine, minor tranquillisers, opiates and non-opiate narcotics. Reports were received from 120 laboratories. Thirty six per cent of laboratories reported on all seven drug classes and 71% on the five classes excluding cannabinoids and cocaine. A single drug screening technique was used by 32% of laboratories whilst 46% were able to perform tests by both immunological and chromatographic techniques. There was a mean level of false positive reporting of 4.3% and an observed level of false negative reports of 8.4%, the latter underestimating the true frequency. The minor tranquillisers, cocaine and benzoyl ecgonine were the most frequently missed analytes. Several false reports had important potential implications for patient care.
authors.affiliation: Department of Pharmacology and Therapeutics, University of Wales College of Medicine, Heath Park, Cardiff, UK.
authors.forename: D
authors.initials: D
authors.lastname: Burnett
authors.forename: S
authors.initials: S
authors.lastname: Lader
authors.forename: A
authors.initials: A
authors.lastname: Richens
authors.forename: B L
authors.initials: BL
authors.lastname: Smith
authors.forename: P A
authors.initials: PA
authors.lastname: Toseland
authors.forename: G
authors.initials: G
authors.lastname: Walker
authors.forename: J
authors.initials: J
authors.lastname: Williams
authors.forename: J F
authors.initials: JF
authors.lastname: Wilson
mesh_terms: D002491:Central Nervous System Agents / Q000652:urine*; D006801:Humans; D007753:Laboratories / Q000592:standards*; D009292:Narcotic Antagonists / Q000652:urine*; D011237:Predictive Value of Tests; D011785:Quality Assurance, Health Care; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000592:standards*; D006113:United Kingdom
chemical_list: D002491:Central Nervous System Agents; D009292:Narcotic Antagonists