Most workplace drug tests screen for five categories of substances: marijuana (THC), cocaine, amphetamines, opioids, and phencyclidine (PCP). That’s the standard 5-panel test, and it’s the same panel required by the Department of Transportation for truckers, pilots, and other safety-sensitive jobs. Some employers go further with 10-panel or even 12-panel tests that add more drug classes.
The Standard 5-Panel Test
The 5-panel urine test is by far the most common workplace drug screen. It checks for:
- Marijuana (THC)
- Cocaine
- Amphetamines, including methamphetamine, MDMA (ecstasy), and MDA
- Opioids, including codeine, morphine, heroin, hydrocodone, hydromorphone, oxycodone, and oxymorphone
- Phencyclidine (PCP)
The opioid category was expanded in 2018 to include prescription painkillers like hydrocodone and oxycodone, which older tests didn’t always catch. There’s also a proposed federal rule, published in September 2025, to add fentanyl and its metabolite norfentanyl to the DOT panel. If finalized, fentanyl testing would become mandatory for all federally regulated transportation workers.
What a 10-Panel Test Adds
Employers in healthcare, law enforcement, or finance often use a 10-panel test. It includes everything in the 5-panel plus several additional drug classes:
- Benzodiazepines (Xanax, Valium, Klonopin)
- Barbiturates (phenobarbital and similar sedatives)
- Methadone
- Alcohol (ethanol)
Some versions of the 10-panel break out oxycodone and methamphetamine/MDMA as their own line items rather than grouping them under broader categories. The exact configuration varies by lab and employer, but these are the substances you can expect. A few employers go even further with 12- or 14-panel tests that may include synthetic cannabinoids, tramadol, or other drugs, though these are less common for routine pre-employment screening.
How Long Substances Stay Detectable in Urine
Detection windows vary widely depending on the substance, how often you use it, your metabolism, and your body composition. For a standard urine test, here are the general timeframes:
- Amphetamines and methamphetamine: 1 to 2 days
- Cocaine: 2 to 4 days for occasional use, up to 22 days with heavy use
- Marijuana: 1 to 3 days for infrequent use, up to 30 days for chronic daily use
Marijuana has the longest and most unpredictable detection window because THC is fat-soluble. It builds up in fatty tissue over time, which is why a daily user can test positive weeks after stopping while someone who used once over a weekend might clear within a few days.
Oral Fluid and Hair Tests
Not every workplace test uses urine. Oral fluid (saliva) tests are becoming more popular because they’re harder to tamper with and can detect same-day use. The tradeoff is a much shorter detection window. Marijuana is typically detectable in saliva for only about 24 hours. Amphetamines, methamphetamine, and benzodiazepines show up for roughly 48 hours. Cocaine and opiates like morphine fall somewhere around 36 hours. Employers often choose saliva tests for post-accident or reasonable-suspicion situations where recent use is the question.
Hair follicle tests work in the opposite direction. A standard hair sample is 1.5 inches long, measured from the scalp, and covers approximately 90 days of drug use since hair grows at roughly half an inch per month. Hair testing is most reliable for detecting cocaine, amphetamines, and opioids. Marijuana had the highest rate of positive results in hair testing studies, but the test is less consistent at catching light or one-time use compared to heavier patterns. Some employers use hair tests for pre-employment screening when they want a broader look at a candidate’s history.
What Happens If You Have a Prescription
A positive result for a prescribed medication doesn’t automatically mean you fail. Workplace drug testing programs use a Medical Review Officer, a licensed physician who reviews every positive result before it goes to your employer. If you test positive for opioids, amphetamines, or benzodiazepines that you’ve been prescribed, the MRO will contact you and ask for verification.
You’ll need to provide one of the following: a copy of your prescription, the labeled medication container, or a medical record showing you were prescribed the drug during the testing period. The MRO may also call your prescribing doctor or pharmacist to confirm the information. Once verified, the result is reported to your employer as negative. Your employer doesn’t learn what medication you’re taking.
There are a couple of caveats. If you’ve been on a high-abuse-potential medication for a long time, the MRO may ask your doctor whether there’s appropriate justification for continued use. For safety-sensitive positions, the MRO can also notify your employer that you’re taking a medication that could affect your ability to do your job safely, without specifying the drug. This is more common in fields like transportation or heavy equipment operation.
For marijuana, the process is more limited. Some states have legal protections for medical marijuana cardholders, but federal drug testing programs and many private employers still treat a positive THC result as a failure regardless of state law. If you have a prescription for a synthetic THC medication like dronabinol, you can present that documentation to the MRO for review.
Types of Tests Employers Use and When
Pre-employment screening is the most common scenario, usually triggered after a conditional job offer. You’ll typically have 24 to 72 hours to report to a collection site. Beyond that, employers may test under several other circumstances: random testing (common in DOT-regulated industries), post-accident testing, reasonable-suspicion testing when a supervisor observes signs of impairment, and return-to-duty testing after a previous violation.
The type of panel and specimen (urine, saliva, or hair) depends on company policy and industry. DOT-regulated employers must use the 5-panel urine test at federally certified labs, though oral fluid testing is now also permitted under federal guidelines. Private employers have more flexibility and can choose whichever panel and method they prefer, subject to state laws that may restrict testing in certain situations.