Test ID: OPRM1
Opioid Receptor, Mu 1 (OPRM1) Genotype for Naltrexone Efficacy
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
Identifying individuals with a higher probability of successful treatment for alcoholism with naltrexone
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Polymerase Chain Reaction (PCR) 5'-Nuclease End point Allelic Discrimination Analysis
(PCR is utilized pursuant to a license agreement with Roche Molecular System, Inc.)
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
CAMPRAL (Acamprosate Calcium)
MOR
Mu-Opioid Receptor (OPRM1)
Naltrexone
Opioid mu Receptor
OPRM1 (mu-Opioid Receptor)
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.
Multiple whole blood EDTA genotype tests can be performed on a single specimen after a single extraction. See Multiple Whole Blood EDTA Genotype Tests in Special Instructions for a list of tests that can be ordered together.
Container/Tube: Lavender top (EDTA)
Specimen Volume: 3 mL
Collection Instructions: Send specimen in original tube.
Additional Information:
1. Bone marrow and liver transplants will interfere with testing. Call Mayo Medical Laboratories at 800-533-1710 or 507-266-5700 for instructions.
2. Transfusions will interfere with testing for up to 4 to 6 weeks. DNA obtained from white cells may not provide useful information for patients who received a recent transfusion of blood that was not leukocyte-reduced. Wait 4 to 6 weeks until transfused cells have left the patient's circulation before drawing the patient's blood specimen for genotype testing.
Forms: New York Clients-Informed consent is required. Please document on request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
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 | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
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 |
|---|---|---|
| Whole Blood EDTA | Ambient (preferred) | |
| Refrigerated | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The mu-opioid receptor (OPRM1) is the primary binding site of action for many opioid drugs and for binding of beta-endorphins. One of the effects of opiate and alcohol use is to increase release of beta-endorphins, which subsequently increases release of dopamine and stimulates cravings. Naltrexone is an opioid antagonist used to treat abuse of opiates, alcohol, and other substances. Naltrexone binds to OPRM1, preventing beta-endorphin binding and subsequently reducing the craving for substances of abuse.(1)
The A355G polymorphism (rs1799971) in exon 1 of the OPRM1 gene (OPRM1) results in an amino acid change, Asn102Asp. Historically, this mutation has been referred to in the literature as 118A->G (Asn40Asp).(2) The G allele leads to loss of the putative N-glycosylation site in the extracellular receptor region, causing a decrease in OPRM1 mRNA and protein levels, but a 3-fold increase in beta-endorphin binding at the receptor.(3) Studies have shown individuals who carry at least 1 G allele have significantly better outcomes with naltrexone therapy including lower rate of relapse (P=0.044), a longer time to return to heavy drinking, and <20% relapse rate after 12 weeks of treatment compared with individuals who are homozygous for the A allele (55% relapse rate).(4) Other studies indicated that 87.1% of G allele carriers had a good clinical outcome, compared with only 54.8% of individuals with the A/A genotype (odds ratio, 5.75; confidence interval, 1.88-17.54).(1) A haplotype-based approach confirmed that the single OPRM1 355A->G locus was predictive of response to naltrexone treatment.(1)
Frequency of the 355G allele varies with ethnicity but ranges between 10% and 40% (European 20%, Asian 40%, African American 10%, and Hispanic 25%).
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.
An interpretive report will be provided.
Interpretation Provides information to assist in interpretation of the test results
An interpretative report will be provided.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Blood transfusions or bone marrow transplantation prior to having blood drawn for DNA analysis can generate false-results as DNA in the specimen may be a mix of patient and donor DNA.
Rare polymorphisms exist that could lead to false-negative or false-positive results. If results obtained do not match the clinical findings, additional testing could be considered.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Somogyi A, Barratt D, Coller J: Pharmacogenetics of opioids. Clin Pharmacol Ther 2007;81:429-444
2. Oroszi G, Anton R, O’Malley S, et al: OPRM1 Asn40Asp predicts response to naltrexone treatment: a haplotype-based approach. Alcohol Clin Exp Res 2009;33:383-393
3. Anton R, Oroszi G, O’Malley, et al: An evaluation of mu-opioid receptor (OPRM1) as a predictor of naltrexone response in the treatment of alcohol dependence. Arch Gen Psychiatry 2008;65:135-144
4. Oslin D, Berrettini W, Kranzler H, et al: A functional polymorphism of the mu-opioid receptor gene is associated with naltrexone response in alcohol-dependent patients. Neuropsychopharmacology 2003;28:1546-1552
Method Description Describes how the test is performed and provides a method-specific reference
Genomic DNA is extracted from whole blood. Genotyping for the OPRM1 A355G allele is performed using a PCR-based 5'-nuclease assay. Fluorescently-labeled detection probes anneal to the target DNA. PCR is used to amplify the section of DNA that contains the polymorphism. If the detection probe is an exact match to the target DNA, the 5'-nuclease polymerase degrades the probe, the reporter dye is released from the effects of the quencher dye, and a fluorescent signal is detected. Genotypes are assigned based on the allele-specific fluorescent signals that are detected. (Package insert: Taqman SNP Genotyping Assay, Applied Biosystems)
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.
Tuesday; 8 a.m.
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.
81479 -Unlisted molecular pathology procedure
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 |
|---|---|---|
| 31912 | OPRM1 Result | In Process |
| 31913 | OPRM1 Interpretation | 69047-9 |
| 31914 | OPRM1 Reviewed by | In Process |
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