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.
- 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.
- Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
Characteristics: 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.
Inheritance: Autosomal co-dominant.
Cause: 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.
Methodology: Polymerase Chain Reaction (PCR) and Fluorescence Monitoring
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: 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.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2008768||OPRM1 Genotype, Specimen|
|2008769||OPRM1 Genotype, Interpretation|
- Opioid receptor sensitivity (Opioid Receptor, Mu (OPRM1) Genotype, 1 Variant)