Which lab studies are performed for evaluation of opioid intoxication?

Updated: Jun 21, 2018
  • Author: David W Dixon, DO; Chief Editor: Glen L Xiong, MD  more...
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Answer

See the list below:

  • Comprehensive urine drug testing is performed when the drug abuse habit of the patient is unknown but suspected. Some labs use the inexpensive thin-layer chromatography (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 are important.

  • Screening and confirmation cut-off concentration for heroin, methadone, morphine, and codeine is 300 ng/mL and are 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.


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