Mental Health Monthly #7: Urine Toxicology in the ED - The Emergency Medical Minute

Mental Health Monthly #7: Urine Toxicology in the ED

This episode of Mental Health Monthly we will be discussing drugs screens in the Emergency Department with Dr. Justin Romano and Eddie Carillo. Dr. Justin Romano is a current psychiatry resident and Eddie Carillo is a licensed mental health therapist. Check out their podcast Millennial Mental Health Channel on all major podcast platforms. Shout out to Dr. Dave Marshall whose grand round presentation this was based on. 

Key Points: 

  • Try not to judge your patient based on the results of their drug screen 
  • Drug screens are used a lot; they are not always accurate 
  • Based on one study there was no significant change in outcome, treatment, disposition or psychiatric course when a drug screen was obtained 
  • Specific good uses for drug screens include new onset of psychiatric symptoms 

Educational Pearls: 

  • 1 in 8 ED visits are due to psychiatric complaints which is up 44% since mid 2000’s 
  • 63% of new psychiatric complaints had a medical cause 
  • Physicians use drug screens commonly in the Emergency Department, but often do not understand their limitations and are often not using them in the most clinically effective manner 
  • Urine is by far the most commonly used in the Emergency Department 
  • UA drug screens are notorious for having false positives and false negatives 
  • Length of clearance from the urine: 
    • Alcohol 12 hours 
    • Methamphetamines/Amphetamines 48 hours 
    • Benzodiazepines 3 days 
    • Opiates 2-3 days 
    • Cocaine 2-4 days 
    • Marijuana dependent on use: 3- 15 days 
    • Phencyclidine (PCP) 8 days 
  • Urine drug screens have a false positive rate of 5-10 % and a false negative rate of 10-15% 
  • False Positive; urine drug screen positive, but drug is not in their body 
    • False positives for amphetamines: bupropion, trazodone, metformin, promethazine, pseudoephedrine, phentermine and atomoxetine 
    • False positives for benzodiazepines: sertraline
    • False positives for cannabis: ibuprofen, naproxen, proton pump inhibitors 
    • False positives for opiates: poppy seeds, antibiotics, Benadryl 
    • False positives for PCP: venlafaxine, ibuprofen and Ambien 
    • False positives for cocaine: amoxicillin 
  • False Negative; urine drug screen negative, but drug is in the body 
    • Benzodiazepines: such as alprazolam, clonazepam, lorazepam or triazolam
    • Cannabinoids: CBD, synthetic marijuana such as K2
    • Opiates: oxycodone, fentanyl, methadone and tramadol 
  • If you get a test that you don’t think is accurate you can always send off for a confirmatory test


Summarized by Emily Mack OMSIII | Edited by Mason Tuttle

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