title: Common Interferences in Drug Testing.
abstract: Interferences relating to laboratory toxicology testing refer to results which differ from their true value and are often encountered in the setting of a drug screen compared with confirmatory testing. Such interferences fall into two general categories; those that cause false positive results (when a drug screen is positive but confirmatory testing is negative) and those that cause false negative results (when a drug screen is negative when in reality the sample donor has ingested the tested substance). Such interferences can result from differences in laboratory testing methodology, reagent and analyte cross reactivity, limits of analyte detection, instrument resolution, reporting cutoff, sample processing, tissue type and sample adulteration among others. Awareness of the possible causes of such interferences are integral to proper laboratory result interpretation and patient management.
authors.affiliation: Oakland University William Beaumont School of Medicine, Rochester, MI, USA; Toxicology and Therapeutic Drug Monitoring Laboratory, Beaumont Laboratories, Beaumont Hospital-Royal Oak, 3601 West 13 Mile Road, Royal Oak, MI 48073, USA. Electronic address: michaelp.smith@beaumont.org.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Smith
authors.affiliation: Department of Pathology, Wayne State University School of Medicine, 540 East Canfield, Detroit, MI 48201, USA; Consolidated Laboratory Management Systems, 24555 Southfield Road, Southfield, Michigan 48075, USA.
authors.forename: Martin H
authors.initials: MH
authors.lastname: Bluth
mesh_terms: D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D015813:Substance Abuse Detection
keywords: Drugs; False negative; False positive; Forensic; Laboratory; Toxicology; Workplace