Summary of common urine drug immunoassays
Observations
- review the list in seizure patients or AMS w/ UDS positive that deny drugs
- list based on Uptodate
Amphetamine
1 to 2 days; 2 to 4 days with heavy use
False-positives: amantadine; atenolol; buproprion; chlorpromazine; desipramine; ephedrine; fluoxetine; labetolol; L-methamphetamine; phentermine; phenylephrine; promethazine; pseudoephedrine; ranitidine; selegiline; synephrine; trazodone
Barbiturates
2 to 4 days (most); 2 to 4 weeks for phenobarbital, primidone
False-positives: ethosuximide; ibuprofen; naproxen
Benzodiazepines
1 to 5 days (most); 2 to 30 days for diazepam, chlordiazepoxide; chronic use does not significantly alter window of detection
False-positives: oxaprozin; sertraline
Cannabinoids (marijuana)
1 to 3 days; 1 month with heavy use
False-positives: efavirenz; hemp-containing foods and hemp seeds; NSAIDS – rare reports of false positives associated with assays that are no longer in use; pantoprazole
Cocaine
2 to 3 days; 7 days with heavy use
False-positives: coca tea, coca leaves
GHB
<24 hours; chronic use does not significantly alter detection
False-positives: NA
Ketamine
1 to 3 days
False-positives: NA
LSD
1 to 3 days
False-positives: NA
Opiates
Heroin
1 to 2 days
False-positives: NA
Opiates
1 to 3 days
False-positives: dextromethorphan; diphenhydramine; nalmefene; naloxone; olanzapine-samidorphan; papaverine; poppy seeds; quinine; quinolones (eg, levofloxacin, ofloxacin); rifampin; verapamil
Hydrocodone, Hydromorphone, Oxycodone, Oxymorphone
1 to 3 days
False-positives: diphenhydramine; nalmefene; naloxone; papaverine; quinine; quinolones; rifampin; verapamil
Buprenorphine
7 days with oral use
False-positives: amisulpride; codeine; dihydrocodeine; methadone; morphine; sulpride; tramadol
Fentanyl
1 to 3 days; 1 to 2 weeks with heavy use
False-positives: labetalol
Meperidine
1 to 3 days
False-positives: NA
Methadone
3 to 7 days
False-positives: chlomipramine; diphenhydramine; doxylamine; quetiapine; tapentadol
Tramadol
2 to 4 days
False-positives: NA
PCP
4 to 7 days
False-positives: desmethylvenlafaxine; dextromethorphan; diphenhydramine; doxylamine; ibuprofen; imipramine; ketamine; meperidine; metronidazole; thioridazine; tramadol; venlafaxine