Opioid Abuse Workup

Updated: May 25, 2018
  • Author: David W Dixon, DO; Chief Editor: Glen L Xiong, MD  more...
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Workup

Laboratory Studies

Abuse and dependence

See the list below:

  • Urine drug screen

  • Detection of drugs in sweat and hair is a recent addition to drug abuse detection technology. However, it is not used widely.

Withdrawal

See the list below:

  • Electrolytes

  • CBC count

  • Urine drug screen is rarely useful.

Intoxication

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.

Addiction

In case of historical or clinical evidence of IV drug abuse, perform the following:

  • LFT

  • Rapid plasma reagent (RPR)

  • Hepatitis viral testing

  • HIV testing

  • Blood cultures (in appropriate clinical setting)

Next:

Imaging Studies

For addiction, in case of historical or clinical evidence of IV drug abuse, perform an x-ray of the lungs (eg, history of injecting drugs contaminated with microcrystalline talc) to search for evidence of pulmonary fibrosis.

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Other Tests

Naloxone challenge test: This test is performed to assess physical dependence. As an intramuscular injection or IV, 0.2-0.8 mg of naloxone is administered.

  • A positive test is indicative of physical dependence and consists of typical withdrawal symptoms and signs. These symptoms and signs usually last for 30-60 minutes.

  • This test is found to be very helpful before starting opiate antagonists for maintenance therapy. Starting opioid antagonists, such as naltrexone, soon after detoxification may cause withdrawal symptoms and discourage patients from further treatment.

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