title: LC-MS/MS extends the range of drug analysis in pain patients.
abstract: The current study addresses the distribution of low concentrations of excreted drugs in the pain patient population in an effort to establish a more rational set of cutoffs for this cohort. To wit, 19 analytes in approximately 8000 urine specimens from pain patients were measured using liquid chromatography tandem mass spectroscopy (LC-MS/MS) methodology. The lower limits of quantitation for the LC-MS/MS were set as the nominal cutoffs for the determination of positive and negative results. The measured concentrations were compared with the Substance Abuse & Mental Health Services Administration (SAMHSA) nominal immunoassay cutoffs, and a subset of "missed samples" was identified for each of the 19 analytes. This "missed samples" subset contained all samples that measured above the LC MS/MS cutoff for a given analyte but below the SAMHSA immunoassay cutoff. The number of "missed samples" divided by the total number of samples measured positive by the LC-MS/MS method defines the percentage of this population that would have been found falsely negative if a prescreen by immunoassay using SAMHSA cutoffs had been conducted. For example, 69% of the specimens that were positive for hydromorphone by LC-MS/MS would have been falsely scored as negative by immunoassay.
authors.affiliation: Millennium Laboratories Research Center, San Diego, California 92127, USA. cmikel@becausepainmatters.com
authors.forename: Charles
authors.initials: C
authors.lastname: Mikel
authors.forename: Perla
authors.initials: P
authors.lastname: Almazan
authors.forename: Robert
authors.initials: R
authors.lastname: West
authors.forename: Bridgit
authors.initials: B
authors.lastname: Crews
authors.forename: Sergey
authors.initials: S
authors.lastname: Latyshev
authors.forename: Amadeo
authors.initials: A
authors.lastname: Pesce
authors.forename: Cameron
authors.initials: C
authors.lastname: West
mesh_terms: D000700:Analgesics / Q000592:standards / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D055118:Medication Adherence; D010146:Pain / Q000188:drug therapy / Q000652:urine*; D012016:Reference Values; D015813:Substance Abuse Detection / Q000592:standards; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014481:United States; D014482:United States Substance Abuse and Mental Health Services Administration
chemical_list: D000700:Analgesics