Opioid Receptor, Mu 1, OPRM1 Genotype, 1 Variant
Ordering Recommendation
Pretherapeutic identification of individuals who may require higher or lower doses of opioid drugs to achieve adequate pain control or have a better response to naltrexone for the treatment of alcohol and/or opioid dependency.
Polymerase Chain Reaction/High Resolution Melt Analysis
Mon, Thu
5-7 days  
New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Submit With Order
Specimen Required
Patient Preparation
Lavender (EDTA) or pink (K2EDTA)  
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL)  
Storage/Transport Temperature
Unacceptable Conditions
Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month  
Reference Interval
By report.  
Interpretive Data
Background Information for Opioid Receptor, Mu 1, OPRM1 Genotype, 1 Variant:
The mu opioid receptor is involved in mediating the clinical response to opioids (agonists and antagonists). OPRM1 c.118A>G has been associated with lower sensitivity to opioid receptor agonists prescribed for pain control (e.g., morphine) and higher sensitivity to opioid receptor antagonists used in the treatment of alcohol and drug dependency (e.g., naltrexone). Risk of side effects to opioids is also associated with this genetic variant.
Autosomal co-dominant.
SNP rs1799971;OPRM1 c.118A>G (p.Asn40Asp); also known as G allele alters response to opioids.
G allele frequency:
African Americans 4 percent, Caucasians 14 percent, Hispanics 24 percent.
Clinical Sensitivity:
Polymerase Chain Reaction (PCR) and Fluorescence Monitoring
Analytical Sensitivity and Specificity:
Greater than 99 percent.
Only the targeted OPRM1 mutation, c.118A>G, will be detected. Diagnostic errors can occur due to rare sequence variations. Risk of therapeutic failure or adverse reactions with opioids may be affected by genetic and non-genetic factors that are not detected by this test. This result does not replace the need for therapeutic or clinical monitoring.

Compliance Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test; however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
New York DOH approval pending. Call for status update.
CPT Code(s)
Component Test Code*Component Chart NameLOINC
2008768OPRM1 Genotype, Specimen 
2008769OPRM1 Genotype, Interpretation 
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • Opioid receptor sensitivity (Opioid Receptor, Mu (OPRM1) Genotype, 1 Variant)