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/Fluorescence Monitoring


Mon, Thu


5-10 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Lavender (EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature


Unacceptable Conditions

Plasma or serum. Heparinized specimens. Frozen specimens in glass collection tubes.


Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month

Reference Interval

By report.

Interpretive Data

Background Information for Opioid Receptor, Mu 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 (eg., morphine) and higher sensitivity to opioid receptor antagonists used in the treatment of alcohol and drug dependency (eg., 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:
Drug dependent.
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. 

Please note the information contained in this report does not contain medication recommendations, and should not be interpreted as recommending any specific medications. Any dosage adjustments or other changes to medications should be evaluated in consultation with a medical provider.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Compliance Category

Laboratory Developed Test (LDT)


Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
2008768 OPRM1 Genotype, Specimen
2008769 OPRM1 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)
Opioid Receptor, mu OPRM1 Genotype, 1 Variant