A standard drug test screens for five categories of substances: marijuana (THC), cocaine, amphetamines, opioids, and phencyclidine (PCP). That’s the baseline. Depending on the situation, your test might check for five substances or more than a dozen, and the specific panel depends on who ordered it and why.
The Standard 5-Panel Test
The most common drug test in the United States is the 5-panel urine test, built around federal workplace testing guidelines set by the Substance Abuse and Mental Health Services Administration (SAMHSA). It covers five drug categories:
- Marijuana (THC): Tests detect the metabolite your body produces after processing THC, not THC itself. The initial screening threshold is 50 ng/mL in urine, with a confirmatory cutoff of 15 ng/mL.
- Cocaine: The test looks for a cocaine byproduct called benzoylecgonine. The initial urine cutoff is 150 ng/mL.
- Amphetamines: This category includes amphetamine, methamphetamine, MDA, and MDMA (ecstasy). The initial urine cutoff is 500 ng/mL.
- Opioids: The panel covers heroin, codeine, morphine, hydrocodone, hydromorphone, oxycodone, and oxymorphone.
- Phencyclidine (PCP): Also known as angel dust.
This is the panel used for most federal employees, Department of Transportation workers, and many private employers. If someone simply says “drug test” without specifying, they’re usually talking about this one.
Expanded Panels: 10, 12, and Beyond
When employers, courts, or treatment programs want broader coverage, they order expanded panels. A 10-panel test includes everything in the 5-panel plus five additional categories: barbiturates (older sedatives), benzodiazepines (anti-anxiety medications), methadone, methaqualone, and propoxyphene. A 12-panel test adds oxycodone and MDMA as separately targeted substances, providing more granular results for those specific drugs.
Some testing programs go even further. Pain management clinics and addiction treatment centers often use custom panels that can test for 16 or more substance categories, including muscle relaxants, sleep aids, and specific prescription opioids. The broader the panel, the more it typically costs, which is why most routine employment screenings stick with five.
What About Fentanyl?
Fentanyl is not included in most standard drug tests. This surprises many people given how prevalent it is, but the standard 5-panel was designed decades ago and has been slow to update. As of September 2025, the Department of Transportation has proposed adding fentanyl and its metabolite to its required testing panel, but the rule has not yet been finalized. Some private employers and treatment programs already test for fentanyl through expanded or custom panels, but you should not assume a standard workplace test will detect it.
Alcohol Testing
Standard drug panels do not include alcohol, but many programs add it separately. A breathalyzer or blood test detects recent drinking within hours. For longer detection, some programs use a urine test that measures a specific alcohol byproduct called EtG. After a few drinks, EtG can show up in urine for up to 48 hours, and after heavier drinking, detection may extend to 72 hours or longer. Programs that monitor sobriety, like court-ordered testing, frequently use EtG because of this wider window.
Synthetic Drugs and Special Testing
Synthetic cannabinoids (K2, Spice) and synthetic cathinones (bath salts) are not detectable on standard drug screens. Synthetic cannabinoids don’t trigger a positive result on THC tests because their chemical structures are different enough to slip past the screening. Specialized commercial labs can test for some of these compounds, but the panels are limited and may not catch newer formulations. Bath salts are similarly difficult to detect and typically require targeted testing that most employers don’t order.
How the Testing Process Works
Drug tests use a two-step process. The first step is an immunoassay, a quick, inexpensive screening that flags samples above a set threshold. It’s designed to be fast, not perfect. If the immunoassay comes back negative, the process stops there.
If the initial screen is positive, the sample moves to confirmatory testing using more precise technology. This second test can identify the exact substance present and measure its concentration with much greater accuracy. The confirmatory test catches errors from the first round, including false positives. It can also detect substances at lower concentrations that the initial screen missed entirely.
This two-step system exists because immunoassays are prone to cross-reactivity. Certain over-the-counter and prescription medications can trigger a false positive on the initial screen. Common cold medications containing pseudoephedrine or phenylephrine can flag as amphetamines. The cough suppressant dextromethorphan (found in many OTC cold remedies) can trigger a positive for opiates. Even some antidepressants and antipsychotics can cause false readings. The confirmatory test distinguishes these from actual drug use, which is why a positive result on the first screen alone is never considered final in regulated testing programs.
Specimen Types and Detection Windows
The type of sample collected affects both what the test can find and how far back it can look.
Urine is the most common specimen. It catches most substances within a window of one to five days for stimulants, one to four days for most opioids, and one to seven days for benzodiazepines. THC is the outlier: occasional users may clear it in a few days, but daily users can test positive for weeks. Methadone has one of the longest urine detection windows at up to 14 days.
Oral fluid (saliva) testing has become increasingly common, partly because it’s harder to tamper with. Collection happens under direct observation, and it’s less invasive than urine or blood. The trade-off is a shorter detection window, typically one to two days for most substances. Federal guidelines now include oral fluid as an approved testing method, with much lower cutoff thresholds. For example, the THC cutoff for oral fluid is just 4 ng/mL on the initial screen, compared to 50 ng/mL for urine.
Hair testing looks back the furthest, typically covering a 90-day window. A standard hair sample is 1.5 inches long, cut close to the scalp, representing roughly three months of growth. Hair tests are less useful for detecting very recent use since it takes about a week for substances to become incorporated into the hair shaft.
Blood testing is the most precise but has the shortest detection window, usually hours to a couple of days. It’s rarely used for routine workplace screening because of the cost and invasiveness, but it’s common in accident investigations and legal cases where pinpointing recent impairment matters.
What Happens if You Take Prescription Medications
If you have a legitimate prescription for a medication that might show up on a drug test, you’ll typically have a chance to disclose it. In regulated federal and DOT testing, a Medical Review Officer (a licensed physician) reviews all positive results before they’re reported. You can provide documentation of your prescription at that stage, and a verified prescription for the detected substance generally results in the test being reported as negative.
Private employers vary in how they handle this, but the principle is similar. The key is that the test itself doesn’t distinguish between prescribed and non-prescribed use. It simply detects the substance. The human review process that follows is what accounts for legitimate medical use.