title: Evaluation of an enzyme immunoassay for the detection of methadone metabolite EDDP [2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine] in urine.
abstract: BACKGROUND
  We evaluated a new EDDP [2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine] enzyme immunoassay (EDDPI; Lin-Zhi International, Inc., Sunnyvale, CA) for the detection of this primary methadone urinary metabolite.
  
  
  METHODS
  All specimens were tested with two different cutoff calibrators at 150 and 300 ng/ml EDDP on an ADVIA 1200 Chemistry System auto-analyzer. Controls containing 0, -25% (negative control), and +25% (positive control) of the cutoff calibrators (Lin-Zhi) were analyzed with each batch. All urine specimens were then analyzed by high-pressure liquid chromatography/ mass spectrometry/mass spectrometry (HPLC-MS/MS) for EDDP.
  
  
  RESULTS
  Approximately, 42% (151) of the 362 specimens yielded positive results by the EDDP assay at 150 and/or 300 ng/ml cutoff values. Of these specimens, HPLC-MS/MS confirmed the presence of EDDP > 25 ng/ml in all 151 specimens. No specimen yielding negative EDDPI results contained EDDP by HPLC/MS/MS. At 150 ng/ml cutoff, the EDDPI demonstrated a sensitivity of 1.00, a specificity of 0.986, and an overall agreement of HPLC/MS/MS of >99%. At 300 ng/ml cutoff, the EDDPI demonstrated a sensitivity of 1.00, a specificity of 0.959, and an overall agreement of HPLC/MS/MS results of 97.5%.
  
  
  CONCLUSIONS
  The Lin-Zhi EDDPI provides a precise, reliable method for the routine detection of methadone metabolite in urine specimens, particularly in pain management compliance testing.
authors.affiliation: Department of Pathology, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Carl E
authors.initials: CE
authors.lastname: Wolf
authors.forename: Ashley
authors.initials: A
authors.lastname: Goldstein
authors.forename: Justin L
authors.initials: JL
authors.lastname: Poklis
authors.forename: Alphonse
authors.initials: A
authors.lastname: Poklis
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D007477:Ions; D013058:Mass Spectrometry; D008691:Methadone / Q000378:metabolism*; D011759:Pyrrolidines / Q000652:urine*
chemical_list: D007477:Ions; D011759:Pyrrolidines; D008691:Methadone; C010724:2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine
keywords: EDDP; enzyme immunoassay; pain management compliance testing; urine drug testing