Standard urine drug tests screen for five core drug classes: marijuana (THC), cocaine, amphetamines, opioids, and phencyclidine (PCP). That’s the baseline 5-panel test used in most workplace and federal screening programs. Expanded panels add benzodiazepines, barbiturates, and other substances depending on the employer or clinical setting.
The Standard 5-Panel Test
The 5-panel urine test is the most widely used drug screen in the United States. It’s the required test for all Department of Transportation workers, federal employees, and many private-sector jobs. Despite the name “5-panel,” the test actually confirms 14 individual substances within those five categories:
- Marijuana: THC and its breakdown products
- Cocaine: detected through a metabolite called benzoylecgonine, which your body produces after processing cocaine
- Amphetamines: amphetamine, methamphetamine, MDMA (ecstasy), and MDA
- Opioids: codeine, morphine, heroin (detected as 6-AM), hydrocodone, hydromorphone, oxycodone, and oxymorphone
- PCP: phencyclidine
Before 2018, federal testing only covered traditional opiates like codeine and morphine. The panel was expanded to include semi-synthetic opioids like oxycodone and hydrocodone, which are found in many common prescription painkillers.
Fentanyl Is Being Added
Fentanyl has not historically been part of the standard 5-panel test, which means it could go undetected in routine screening. That’s changing. In January 2025, the Department of Health and Human Services added fentanyl and its metabolite norfentanyl to the authorized federal testing panels. The Department of Transportation has proposed matching this change for all transportation workers. The testing cutoff is extremely low at 1 ng/mL, making it sensitive enough to catch even small exposures.
Expanded Panels: 10, 12, and Beyond
Many employers, courts, and treatment programs use expanded panels that go beyond the standard five categories. A 10-panel test typically adds:
- Benzodiazepines: anti-anxiety medications like alprazolam, diazepam, lorazepam, and clonazepam
- Barbiturates: older sedatives like phenobarbital
- Methadone
- Propoxyphene
- Methaqualone
A 12-panel test often adds MDMA (if not already covered) and extended opioids. Some specialized panels ordered in clinical or pain management settings can test for dozens of specific substances, including synthetic cannabinoids, kratom, gabapentin, and muscle relaxants. The scope depends entirely on who ordered the test and why.
How Long Each Drug Stays Detectable
Detection windows vary widely depending on the substance, how often you use it, and your individual metabolism. Here are the general timeframes for urine detection:
- Marijuana (light use): 1 to 3 days
- Marijuana (heavy use): 3 weeks or longer
- Cocaine: 1 to 4 days
- Amphetamine: 1 to 5 days
- Methamphetamine: 1 to 4 days
- Opioids (codeine, morphine, oxycodone): 1 to 4 days
- Heroin: less than 1 day
- Benzodiazepines: 1 to 10 days, depending on the specific medication
Marijuana has the widest detection range of any commonly tested substance. THC is fat-soluble, meaning it accumulates in body fat and releases slowly over time. A daily user can test positive for three weeks or more after stopping, while someone who used once might clear the test within a few days. Hydration, body fat percentage, and metabolic rate all influence how quickly any substance clears your system. A very diluted urine sample can lower drug concentrations below the test’s threshold, which is why labs also measure creatinine levels to check whether a sample is too dilute to be valid.
How the Testing Works
Urine drug tests happen in two stages. The first is an immunoassay, a quick, inexpensive screening that flags samples as either negative or “presumptive positive.” This initial screen is designed to cast a wide net. It’s good at ruling out drug-free samples, with about 96% specificity, but it’s not perfect at confirming positives.
If the immunoassay flags a sample, a second confirmatory test is run using a more precise technique called mass spectrometry. This method identifies the exact chemical compounds present and their concentrations, eliminating most false positives. It can also detect substances at lower concentrations that immunoassays miss. Research comparing the two methods found that immunoassays had sensitivity as low as 36% for certain benzodiazepines, meaning they missed more than half of true positives for those drugs. The confirmatory test catches what the initial screen cannot.
Cutoff Levels That Determine a Positive Result
A positive result doesn’t mean the lab found zero traces of a drug. Every test has a cutoff concentration, measured in nanograms per milliliter (ng/mL), below which a result is reported as negative. These thresholds exist to reduce false positives from incidental or environmental exposure. Federal cutoff levels for the initial screen include:
- Marijuana metabolite: 50 ng/mL
- Cocaine metabolite: 150 ng/mL
- Amphetamines: 500 ng/mL
- Codeine/Morphine: 2,000 ng/mL
- Oxycodone/Oxymorphone: 100 ng/mL
- PCP: 25 ng/mL
- Fentanyl: 1 ng/mL
If a sample tests positive on the initial screen, confirmatory testing uses lower cutoffs to verify the result. For instance, the marijuana confirmatory cutoff drops to 15 ng/mL, and cocaine drops to 100 ng/mL. Non-federal tests ordered by private employers or courts may use different thresholds.
Medications That Can Trigger False Positives
The initial immunoassay screen can be fooled by medications that share a similar chemical structure with the drugs being tested. False positives for amphetamines are the most common. A wide range of everyday medications have been documented to cause them, including bupropion (an antidepressant and smoking-cessation aid), certain antihistamines like diphenhydramine and brompheniramine, the antipsychotic quetiapine, and even over-the-counter nasal decongestant inhalers.
Other false positives are also possible. Dextromethorphan, the cough suppressant found in many cold medicines, can trigger a false positive for PCP. Ibuprofen and naproxen have been linked to false positives for marijuana and barbiturates in older assays. The antidepressants sertraline, trazodone, and venlafaxine have each been associated with false positives for benzodiazepines or other drug classes.
If you’re taking any prescription or over-the-counter medication and are facing a drug test, this is worth knowing. A false positive on the initial screen will be caught by the confirmatory mass spectrometry test in most regulated testing programs. But in settings that don’t use confirmatory testing, a false positive could stand. You’re generally allowed to disclose your medications to the Medical Review Officer who interprets the results.