Summary of common urine drug immunoassays

Assay	Substance detected^*	Timeframe for positive urine assay with acute and chronic exposure^¶	False-positives^Δ	Comments
Amphetamine	Amphetamine Methamphetamine MDMA MDA MDEA	1 to 2 days 2 to 4 days with heavy use	Amantadine Atenolol Buproprion Chlorpromazine Desipramine Ephedrine Fluoxetine Labetolol L-methamphetamine Phentermine Phenylephrine Promethazine Pseudoephedrine Ranitidine Selegiline Synephrine Trazodone	Amphetamine assays have poor specificity due to structural similarity of many drugs, medications (eg, nasal decongestants), and herbal supplements (eg, ephedrine). False-positives result from structurally similar substances, drugs that are metabolized to structurally similar molecules in vivo, and structurally dissimilar molecules. Amphetamine panels are required to detect amphetamine only, but often detect multiple amphetamines; this varies by manufacturer. Specific assays for MDMA, MDA, MDEA, and other designer amphetamines are available. Atomoxetine and methylphenidate are not detected by routine screening.
Barbiturates	Various barbiturates (eg, phenobarbital, butalbital) Secobarbital	2 to 4 days (most) 2 to 4 weeks for phenobarbital, primidone	Ethosuximide Ibuprofen Naproxen	Not routinely performed in clinical settings. If testing specifically for phenobarbital, the quantitative serum/plasma assay is preferable and available in most hospital laboratories.
Benzodiazepines	Various benzodiazepines (eg, diazepam) Oxazepam, nordiazepam Most assays do not detect alprazolam or lorazepam	1 to 5 days (most) 2 to 30 days for diazepam, chlordiazepoxide Chronic use does not significantly alter window of detection	Oxaprozin Sertraline	Due to poor sensitivity and variable cross-reactivity of assays, not recommended as a urine immunoassay in the emergency setting. No single assay is known to detect all benzodiazepines. Specific assays are necessary to detect alprazolam, flunitrazepam, lorazepam, and other benzodiazepines which are not metabolized to oxazepam. "Z" drugs (eszopiclone, zaleplon, zolpidem, zopiclone) are not detected by benzodiazepine screening.
Cannabinoids (marijuana)	Delta9-THC 11-nor-delta9-THC-carboxylic acid 11-nor-delta8-THC-carboxylic acid 11-hydroxy-delta9-THC	1 to 3 days 1 month with heavy use	Efavirenz Hemp-containing foods and hemp seeds NSAIDS – rare reports of false positives associated with assays that are no longer in use Pantoprazole	False-positive urine testing due to secondhand smoke exposure is considered unlikely or impossible. Consumption of hemp-containing foods is extremely unlikely to cause a positive test. Differentiation between positive tests from marijuana use and hemp oil is generally not possible. No longer recommended as a required urine immunoassay due to the extended window of detection, widespread legalization of medical or recreational cannabis use, and lack of evidence of relevant acute adverse effects. Synthetic cannabinoids that are widely misused are not detected by routine cannabinoid assays. Specific assays capable of detecting many synthetic cannabinoids are available. Dronabinol and nabiximols can cause a true-positive result.
Cocaine	Cocaine Benzoylecgonine	2 to 3 days 7 days with heavy use	Coca tea, Coca leaves	Benzoylecgonine is a cocaine metabolite. Cocaine assays have high specificity and overall accuracy. Can also be positive after medical use of topical anesthetics containing cocaine.
GHB	GHB GBL 1,4 butanediol	<24 hours Chronic use does not significantly alter detection		Detection is difficult because of brief half-life and technical problems. Not routinely performed but often included in screening panel for drug-facilitated sexual assault. GHB is both an endogenous neurotransmitter and a drug, which complicates interpretation and requires a threshold to avoid false-positives.
Ketamine	Ketamine Norketamine	1 to 3 days		Not commonly used in clinical settings.
LSD	LSD 2-oxo-3-hydroxyLSD	1 to 3 days		Not commonly used in clinical settings.
Opiates/Opioids
*Derived from natural plant matter*
Heroin	Heroin 6-monoacetyl morphine	1 to 2 days		Heroin is diacetyl morphine, which is metabolized to 6-monoacetyl morphine and morphine.
Opiates	Morphine Codeine	1 to 3 days	Dextromethorphan Diphenhydramine Nalmefene Naloxone Olanzapine-samidorphan Papaverine Poppy seeds Quinine Quinolones (eg, levofloxacin, ofloxacin) Rifampin Verapamil	Poppy seeds contain codeine and morphine. The threshold for detection for workplace assays (2000 ng/mL) is such that routine poppy seed consumption is unlikely to cause positive results. However, many institutions use a lower threshold (300 ng/mL) and confirmatory testing can detect morphine and codeine from routine consumption. Routine opiate screening does not detect synthetic opioids, such as buprenorphine, fentanyl, methadone, meperidine, pentazocine, propoxyphene, tramadol, and loperamide. Depending on the cross-reactivity of the assay, hydrocodone, hydromorphone, or heroin (6-monoacetyl-morphine) can be detected.
*Semi-synthetic*
Hydrocodone	Norhydrocodone Hydrocodone	1 to 3 days	Diphenhydramine Nalmefene Naloxone Papaverine Quinine Quinolones Rifampin Verapamil
Hydromorphone	Norhydromorphone Hydromorphone
Oxycodone	Oxycodone Noroxycodone Oxymorphone Noroxymorphone
Oxymorphone	Noroxymorphone Oxymorphone
*Synthetic*
Buprenorphine	Buprenorphine Norbuprenorphine	7 days with oral use	Amisulpride Codeine Dihydrocodeine Methadone Morphine Sulpride Tramadol
Fentanyl	Fentanyl Norfentanyl Possibly fentanyl analogs	1 to 3 days 1 to 2 weeks with heavy use	Labetalol	May also detect fentanyl analogs, especially those with acryl, butyryl, or furanyl modifications.
Meperidine	Normeperidine Meperidine	1 to 3 days
Methadone	Methadone EDDP	3 to 7 days	Chlomipramine Diphenhydramine Doxylamine Quetiapine Tapentadol	There is a separate urine immunoassay specifically for the methadone metabolite EDDP which can aid identifying patients who are diverting their methadone by adding it to their urine samples to demonstrate medication adherence.
Tramadol	Tramadol Nortramadol (desmethyltramadol)	2 to 4 days
PCP	PCP	4 to 7 days	Desmethylvenlafaxine Dextromethorphan Diphenhydramine Doxylamine Ibuprofen Imipramine Ketamine Meperidine Metronidazole Thioridazine Tramadol Venlafaxine	Dozens of congeners of PCP with similar clinical effects exist, and these are variably detected or not detected by PCP screening. Many causes of false-positive screening exist, and due to the low prevalence of PCP use in most settings, the likelihood of a true positive test is low.

EDDP: 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine; GBL: gamma-butyrolactone; GHB: gamma-hydroxybutanoic acid; LSD: lysergic acid diethylamide; MDA: 3,4-methylenedioxyamphetamine; MDMA: 3,4-methylenedioxymethamphetamine; MDEA: 3,4-methylenedioxy-N-ethylamphetamine; NSAIDs: nonsteroidal antiinflammatory drugs; PCP: phencyclidine; THC: tetrahydrocannabinol.

* The specific drug or metabolite that the immunoassay was designed to detect is italicized.

¶ Generally, screening tests for particular drugs become positive within minutes to hours once the drug becomes bioavailable.

Δ False-positivity varies by assay; this list is not exhaustive.

Courtesy of Robert J Hoffman, MD.

Graphic 95110 Version 12.0

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Summary of common urine drug immunoassays