Test ID: MTDNS
Methadone, Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Compliance monitoring of methadone therapy in patients being treated for heroin addiction
Assessing toxicity
Method Name A short description of the method used to perform the test
Gas Chromatography-Mass Spectrometry (GC-MS)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Methadone (Dolophine)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Red top
Specimen Volume: 4.5 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | Mild OK; Gross reject |
| Other | Serum gel tube |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days |
| Frozen | 14 days | |
| Ambient | 72 hours |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Methadone (Dolophine) is an opioid receptor agonist with analgesic and pharmacologic properties similar to morphine. It can be administered orally and provides analgesia for approximately 24 hours. The I-racemate of the drug is active, while the d-racemate has little activity. Methadone has properties that make it useful for treating heroin addiction. Sedation ensues with higher doses, which is an undesirable side effect. Administered in small doses of 5 to 20 mg, the drug occupies the opioid receptor for prolonged periods of time, blocking the action of morphine, precluding the euphoric effect that heroin addicts seek. Addicts who self-administer heroin while taking methadone experience no effect from the heroin, and addicts who take large methadone doses do not experience euphoria, only sedation, miosis, respiratory depression, hypotension, and dry-mouth. Tolerant patients may require doses of 60 to 100 mg per day.
Methadone is metabolized by demethylation (cytochrome P[450] 2D6 [CyP 2D6]) to 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine and to 2-ethyl-5-methyl-3,3-diphenylpyrrolidinr. Individuals with genetic deficiencies of CyP 2D6 or those who are coadministered amiodarone, paroxetine, protease inhibitor antiretrovirals, chlorpheniramine, or other drugs that inhibit CyP 2D6 will accumulate methadone and be at risk for associated toxicity.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Single dose: 30-90 ng/mL
Maintenance dose: 400-1,000 ng/mL
Interpretation Provides information to assist in interpretation of the test results
The minimal effective serum concentration for analgesia is 30 ng/mL. Peak therapeutic serum concentrations of 30 to 90 ng/mL occur 4 hours after dose. Patients continuously administered methadone develop tolerance and have higher serum concentrations than indicated by the reference range; these patients may tolerate concentrations up to 400 ng/mL. Methadone concentrates in serum; the ratio of blood to serum methadone is 0.75.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Because methadone has a wide therapeutic index and dose-dependent toxicity, routine drug monitoring is not indicated in all patients.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Goodman LS, Gillman A, Hardman JG, et al: The pharmacological basis of therapeutics. Ninth edition. Edited by JG Hardman, LE Limbird. New York, McGraw-Hill Book Company, 1996, pp 544-555
2. Baselt RC: Disposition of toxic drugs and chemicals in man. Fifth edition. Foster City, CA, Chemical Toxicology Institute, 2000, pp 523-527
Method Description Describes how the test is performed and provides a method-specific reference
Gas chromatography-mass spectrometry(Enger R: Modified from United Chemical Technologies, Inc., method entitled "Methadone in Urine For GC/MS Confirmations using: 200mg Clean Screen Extraction Column [ZSDAU020 or ZCDAU020]"; Unpublished Mayo information)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Thursday, Sunday
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83840
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 83131 | Methadone, S | 3772-1 |
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