title: Suitability of the DRI Hydrocodone/Hydromorphone Immunoassay in the Clinical Environment at a Lower Cutoff: Validation With LC-MS/MS Analysis.
abstract: We evaluated the analytical performance of the DRI hydrocodone/hydromorphone assay by comparing semiquantitative values obtained by this assay with values obtained by a liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) method. We also evaluated the possibility of lowering the cutoff of the DRI assay from 300 to 100 ng/mL.
  
  
  
  We compared semiquantitative values obtained by the DRI assay in 97 specimens with values obtained by the LC-MS/MS method including 10 specimens containing hydrocodone and/or hydromorphone concentrations between 105.0 and 145.0 ng/mL (determined by LC-MS/MS) to determine the sensitivity at 100 ng/mL. In addition, several opioids at a concentration of 5000 ng/mL were also analyzed by the DRI assay to determine its specificity.
  
  
  
  We observed no false-negative result using the DRI immunoassay in 96 specimens that showed semiquantitative values at 100 ng/mL or higher. However, one specimen containing 110 ng/mL of hydrocodone was false negative with the DRI assay (semiquantitative value 88 ng/mL, below 100 ng/mL cutoff). The semiquantitative values produced by DRI showed poor correlation with values determined by the LC-MS/MS method. The sensitivity of the DRI assay at 100 ng/mL was 90%, and the assay was very specific showing minimal cross-reactivity only with oxycodone and oxymorphone.
  
  
  
  DRI immunoassay for hydrocodone/hydromorphone is a cost-effective method of screening urine specimens in the clinical environment at a lower cutoff of 100 ng/mL.
authors.affiliation: *Physician's Choice Laboratory Services, Rock Hill, SC; and †Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Dixon
authors.forename: Amitava
authors.initials: A
authors.lastname: Dasgupta
mesh_terms: D000701:Analgesics, Opioid / Q000652:urine; D002853:Chromatography, Liquid / Q000379:methods; D006801:Humans; D006853:Hydrocodone / Q000652:urine*; D004091:Hydromorphone / Q000652:urine*; D007118:Immunoassay / Q000379:methods; D010098:Oxycodone / Q000652:urine; D010111:Oxymorphone / Q000652:urine; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D000701:Analgesics, Opioid; D006853:Hydrocodone; D010111:Oxymorphone; D010098:Oxycodone; D004091:Hydromorphone