Open AccessEvaluation of an Enzyme Immunoassay for the Detection of Methadone Metabolite EDDP [2‐Ethylidene‐1,5‐Dimethyl‐3,3‐Diphenylpyrrolidine] in Urine
Author(s) -
Wolf Carl E.,
Goldstein Ashley,
Poklis Justin L.,
Poklis Alphonse
Publication year - 2014
Publication title -
journal of clinical laboratory analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 50
eISSN - 1098-2825
pISSN - 0887-8013
DOI - 10.1002/jcla.21657
Subject(s) - chromatography , metabolite , high performance liquid chromatography , immunoassay , urine , chemistry , mass spectrometry , detection limit , medicine , antibody , biochemistry , immunology
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%. Conclusion 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.