Use

Methadone is prescribed to patients for the alleviation of opioid addiction withdrawal symptoms and analgesic purposes. The test is a screening assay using a homogeneous enzyme immunoassay method of analysis. Presumptive positive screening tests are reflexed to a more specific and sensitive liquid chromatography mass spectroscopy (LC/MS/MS) confirmation test. Therapeutic urine drug monitoring of methadone and its metabolite EDDP is important for ensuring compliance to treatment strategies, as well as ensuring non‑diversion for illicit purposes strategies. Urine or oral fluid are the specimens of choice for routine monitoring of patients taking prescription drugs. Use of serum/plasma should be limited to anuretic patients, or where a patient's clinical appearance does not coincide with their prescribed medications. No single monitoring approach provides adequate information about the pattern or dose of patient drug use. Quantitative values cannot be used to assess the drug dose, because the drug is extensively metabolized and excreted in the urine.