The Urine Drug Screen can be an important tool in evaluating patients for appropriateness of chronic pharmacotherapy, as well as in identifying sources of delirium and altered mental status. However, interpretation of results can be a daunting task. The following questions will need to be answered in order to properly understand the UDS.

  • How should the urine drug screen be utilized in pharmacy practice?1
  • How should the urine drug screen be used in chronic pain management?2
  • How sensitive is the urine drug screen?3 If a patient last used a substance yesterday, will the test pick it up today?
  • What are some common agents that may cause false positives on the UDS?4-5
  • Should I order confirmatory testing?6 What good will it do?
  • Could the use of one opioid cause a positive result for another?7 How are the various opioids metabolized?
  • Can we test for novel drugs of abuse?8-9


  1. Moeller K. Struggles with urine drug screens. Presented at the CPNP annual meeting (2018). [Weblink]
  2. Cone EJ, Caplan YH. Urine toxicology testing in chronic pain management. Postgrad Medicine. 2nd ed. 2009;121(4):91-102. DOI: 10.3810/pgm.2009.07.2035. PubMed PMID: 19641275.
  3. Moeller KE, Kissack JC, Atayee RS, Lee KC. Clinical interpretation of urine drug tests: What clinicians need to know about urine drug screens. Mayo Clinic Proceedings. 2017;92(5): 774-96 [PubMed]
  4. Saitman A, Park H-D, Fitzgerald RL. False-positive interferences of common urine drug screen immunoassays: a review. J Anal Toxicol. 2014;38(7):387-96. DOI: 10.1093/jat/bku075. PubMed PMID: 24986836.
  5. Brahm NC, Yeager LL, Fox MD, Farmer KC, Palmer TA. Commonly prescribed medications and potential false-positive urine drug screens. Am J Health Syst Pharm. 2010;67(16):1344-50. DOI: 10.2146/ajhp090477. PubMed PMID: 20689123.
  6. Premier Biotech. Laboratory screening and confirmation – defined. 2017.  [Weblink]
  7. Milone MC. Laboratory testing for prescription opioids. J. Med. Toxicol. 2nd ed. 2012;8(4):408-16. DOI: 10.1007/s13181-012-0274-7. PubMed PMID: 23180358; PubMed Central PMCID: PMC3550258.
  8. Dasgupta A. Challenges in laboratory detection of unusual substance abuse: Issues with magic mushroom, peyote cactus, khat, and solvent abuse. Adv Clin Chem. 2017; 78: 163-186. [PubMed]
  9. Nieddu M, Burrai L, Baralla E, et al. ELISA detection of 30 new amphetamine designer drugs in whole blood, urine and oral fluid using Neogen® "smphetamine" and "methamphetamine/MDMA" kits. J Anal Toxicol. 2016;40(7): 492-7. [Pubmed]