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Methadone Screen


Immunoassay screen to for qualitative detection of methadone in urine.

Methadone, a synthetic opioid, has been used in the treatment of heroin addiction. Methadone compliance is essential and can be effectively monitored by urine screening for methadone or its metabolite. When methadone is ingested, it is rapidly metabolized in the liver. The primary methadone metabolite is formed by N-demethylation to normethadone. However, normethadone is rarely detected as it readily dehydrates to form 2-ethylidene-1, 5-dimethyl-3, 3-diphenylpyrrolidine, commonly known as EDDP. Both TLC and GC methods are laborious and subject to interference. 

The methadone screening assay uses specific antibodies, which can detect methadone in urine. The assay is based on the competition of an enzyme glucose-6-phosphate dehydrogenase (G6PDH) labeled drug and the drug from the urine sample for a fixed amount of specific antibody binding sites. In the absence of drug from the sample, the specific antibody binds to the drug labeled with G6PDH and the enzyme activity is inhibited. This phenomenon creates a direct relationship between the drug concentration in the urine and the enzyme activity. The enzyme G6PDH activity is determined spectrophotometrically at 340 nm by measuring its ability to convert nicotinamide adenine dinucleotide (NAD) to NADH.

Test Utility

This test is used to detect the presence of illicit or prescription medications in urine.

Specimen Collection and Preparation

At least 1 mL of urine should be collected in a urine specimen container.

Specimen Storage and Stability

Urine specimen should be stored under refrigerated conditions (2–8°C) until analysis. Samples will also be stored under refrigerated conditions on site for 2 weeks post analysis.

Specimen Rejection

  • Insufficient sample volume

  • Specimen labeled incorrectly or not labeled

  • Specimen validity tests indicate adulterated test

Reference Pages


Monday – Saturday

Result available within 24-48 hours of receipt in laboratory

NOTE: Specimens are refrigerated (2-8°) for 14 days before disposal


Vibra Health Laboratory

1307- A, Allen Dr

Troy, MI 48083

(248) 846-0663

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