Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1092 page)

   Several vendors offer assays in semiquantitative mode.

   Immunoassay available specifically for heroin metabolite-6-acetylmorphine: cutoff concentration 10 ng/mL; <1% cross reactivity with morphine, codeine, and synthetic opioids

   Screening in blood, serum

   Immunoassay-based technology (FPIA, ELISA, RIA)

   Opioid specific except for general “opiates,” which targets morphine with a cutoff concentration typically of 10 ng/mL

   Target (cutoff concentration)

   Fentanyl <1 ng/mL

   Methadone 10–50 ng/mL; <5% cross-reactivity with methadol

   Oxycodone 10–50 ng/mL; >50% cross-reactivity with oxymorphone

   
D
-Propoxyphene 10–50 ng/mL; >400% cross-reactivity with norpropoxyphene

   Confirmation/quantitation in serum, urine

   Confirmation of urine samples often includes hydrolysis to cleave the glucuronide bond. In this case, the concentration provided is total drug (compared with free or unbound drug).

   Common opioid confirmation profiles will include 6-acetylmorphine, morphine, codeine, oxycodone, oxymorphone, hydrocodone, and hydromorphone with limit of quantitation drug dependent but ranging 5–25 ng/mL.