Urine drug tests: Ordering and interpretation

Neelima J Kale

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Urine drug testing is an essential component of monitoring patients who are receiving long-term opioid therapy, and it has been suggested for patients receiving long-term benzodiazepine or stimulant therapy. Family physicians should be familiar with the characteristics and capabilities of screening and confirmatory drug tests. Immunoassays are qualitative tests used for initial screening of urine samples. They can give false-positive and false-negative results, so all results are considered presumptive until confirmatory testing is performed. Immunoassays for opioids may not detect commonly prescribed semisynthetic and synthetic opioids such as methadone and fentanyl;similarly, immunoassays for benzodiazepines may not detect alprazolam or clonazepam. Immunoassays can cross-react with other medications and give false-positive results, which have important implications for a patient’s pain treatment plan. False-negative results can cause missed opportunities to detect misuse. Urine samples can be adulterated with other substances to mask positive results on urine drug testing. Family physicians must be familiar with these substances, the methods to detect them, and their effects on urine drug testing.

Original languageEnglish (US)
JournalAmerican Family Physician
Issue number1
StatePublished - Jan 1 2019

ASJC Scopus subject areas

  • Family Practice


Dive into the research topics of 'Urine drug tests: Ordering and interpretation'. Together they form a unique fingerprint.

Cite this