Methadone and Metabolites, Serum
Use
This test is useful for compliance monitoring of methadone and assessment of methadone toxicity. Methadone, a long-acting synthetic opioid analgesic, binds to mu-opioid receptors and has actions similar to morphine, primarily affecting the central nervous system and smooth muscle organs. It is used therapeutically for analgesia, sedation, and opioid addiction maintenance or detoxification.
Special Instructions
The test requires a serum sample collected in a red top tube. SST or serum gel tubes are not acceptable. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial. Routine drug monitoring is not always necessary due to the wide therapeutic index of methadone and its dose-dependent toxicity.
Limitations
Specimens collected in serum gel tubes are not acceptable because the drug can absorb on the gel and lead to falsely decreased concentrations. Methadone has a wide therapeutic index, resulting in significant interindividual variability in metabolism and elimination, with half-lives ranging from 7 to 59 hours or more.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 96602-8
- 3772-1
- 60071-8
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.0 mL
Minimum Volume
0.5 mL
Container
Plastic vial
Collection Instructions
Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial. Serum gel tubes are not acceptable.
Storage Instructions
Refrigerated (preferred), 28 days; Ambient, 14 days; Frozen, 28 days
Causes for Rejection
Specimens collected in serum gel tubes
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 28 days |
| Frozen | 28 days |