From the Guidelines
Synthetic opioids will not test positive for morphine or codeine on standard drug tests. This is because synthetic opioids like fentanyl, methadone, tramadol, and oxycodone have different chemical structures than natural opiates (morphine and codeine) and are not detected by basic opiate immunoassay screens 1.
Key Points to Consider
- Synthetic opioids require specific testing for detection, as they are not included in standard opiate immunoassay panels 1.
- Semi-synthetic opioids like hydrocodone and hydromorphone may occasionally cause positive results for morphine or codeine on some tests due to their closer structural similarity 1.
- Comprehensive toxicology screens or specific tests for synthetic opioids are required to detect these substances 1.
- It is essential to disclose all prescribed medications to testing authorities to avoid false interpretations 1.
Implications for Clinical Practice
- Clinicians should be aware of the limitations of standard opiate immunoassay tests and order specific tests for synthetic opioids when necessary 1.
- Patients should be informed about the importance of disclosing all prescribed medications to ensure accurate test results 1.
- Unexpected results should be discussed with the patient and the local laboratory or toxicologist to determine the best course of action 1.
From the Research
Synthetic Opioids and Morphine/Codeine Positivity
- Synthetic opioids are a class of drugs that are designed to mimic the effects of natural opioids, such as morphine and codeine 2.
- However, synthetic opioids are not typically positive for morphine or codeine in standard drug tests, as they have different chemical structures and metabolites 2.
- Some synthetic opioids, such as buprenorphine and fentanyl, have unique metabolites that can be detected in urine or blood tests, but these metabolites are not the same as morphine or codeine 2.
Detection of Synthetic Opioids
- The detection of synthetic opioids in biological samples, such as urine or blood, typically requires specialized testing methods, such as gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) 3, 4, 5.
- These methods can detect the presence of specific synthetic opioids and their metabolites, but may not detect morphine or codeine 3, 4, 5.
- The use of normetabolites as biomarkers of synthetic opioid use can enhance the effectiveness of monitoring programs for pain patients 2.
Limitations of Standard Drug Tests
- Standard drug tests, such as immunoassay screening, may not detect synthetic opioids or their metabolites, and may produce false negative results 4, 2.
- The use of more sensitive and specific testing methods, such as GC-MS or LC-MS/MS, can improve the detection of synthetic opioids and their metabolites 3, 4, 5.