In patients with suspected opioid intoxication, the following should be noted:
Comprehensive urine drug testing is performed when the drug abuse habit of the patient is unknown but suspected. Some labs use the inexpensive TLC procedure. This test has low sensitivity for commonly used drugs. TLC cannot detect fentanyl.
Enzyme immunoassay and radioimmunoassay are more sensitive than TLC, but they are less specific because molecules with similar functional groups cross-react with antibodies. These are relatively inexpensive tests.
Gas-liquid chromatography (GLC) and gas chromatography–mass spectrometry (GC-MS) are very sensitive and specific tests, but they are time-consuming, labor-intensive, and expensive.
In drug abuse detection, knowing the half-life of the drug, the biotransformation of the drug, and the excretion route of the drug is important.
Screening and confirmation cut-off concentration for heroin, methadone, morphine, and codeine is 300 ng/mL and can be detected in urine within 1-4 days.
False-negative results occur more easily than false positives, simply because once a test is screened negative, it is not tested further. The federal government requires that the results of the drug testing programs go directly to medical review offices to prevent improper interpretation of drug testing data.
Blood alcohol levels also may be tested.
For more on the workup of opioid intoxication, read here.
Medscape © 2016 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Mary L. Windle. Fast Five Quiz: Do You Know Best Practices for Opioid Use and How to Confront Abuse? - Medscape - Sep 21, 2016.
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