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Urine Drug Screen (Panel Result)

A urine test that checks for several drugs at once. A positive screen is a first look, and a second test is used to check it.

AI-verified against cited sources. Awaiting expert reviewAlso called UDS, UDTLOINC 69739-1

What it is

A urine drug screen checks a urine sample for drugs and their breakdown products. Most labs use a fast first test called an immunoassay. It reports a positive result only when a drug is at or above a set cutoff level. Each lab chooses its own panel (the list of drugs) and its own cutoffs, so two labs can give different answers on the same sample. Your report may show one overall result plus a result for each drug.

Why it matters

Doctors order this test for many reasons, such as an emergency visit, pain or addiction treatment, a check before surgery or a job, or a court or program requirement. The first test is a screen, so it can be wrong in both directions. It can read positive because of a look-alike medicine or food. It can read negative if a drug is not on the panel or the urine was very dilute. A second, more exact test is often used to confirm a result that matters.

If it’s high

A positive screen means the test found something at or above the lab's cutoff. It does not prove which drug was taken, how much, or when. It also does not say whether the drug was prescribed. Because screens can react to look-alike substances, a confirmation test is often used before anyone acts on the result.

Common causes

  • A medicine that was prescribed to you or that you bought over the counter
  • A look-alike substance that reacts with the screening test, such as some prescription and over-the-counter medicines, or poppy seeds on opioid tests
  • Use of a drug outside of medical care
  • A drug you took without knowing what else was in it
  • A lab or sample mix-up (rare)

What can help

  • Give your clinician or the lab a full list of your medicines, supplements and recent foods
  • Ask whether your sample was sent for a confirmation test, which is more exact than the screen
  • Ask which drugs are on the panel and what cutoff the lab used for each
  • If you are worried about your own or someone else's substance use, your clinician can talk through support options without judgment

What can affect your result

  • Which drugs are on the panel, which differs by lab and by program
  • The cutoff each lab uses for each drug
  • How long ago a drug was taken, how much, and how often
  • How dilute the urine is, since drinking a lot of fluid can lower drug levels; labs check creatinine and specific gravity to judge this
  • Medicines, supplements and foods that look like a drug to the test (cross-reactivity)
  • Whether a positive screen was confirmed with a second, more exact test (GC-MS or LC-MS/MS)
  • Screening tests are immunoassays. They can react to look-alike chemicals, so some medicines and foods can cause a false positive. Poppy seeds can do this for opioid tests, and published reports describe loperamide (fentanyl tests), quetiapine and vortioxetine (methadone tests) and mebeverine (MDMA tests).
  • A class test can miss specific drugs in that class. A standard opiate screen does not detect fentanyl or methadone, and it may miss oxycodone and buprenorphine.
  • Very dilute urine can push a drug level below the cutoff, so the result reads negative.
  • Each lab and each program sets its own panel and cutoffs, so the same sample can read differently at different labs.

Any time of day. Collection is sometimes supervised, especially in treatment, workplace and legal settings, and labs check that the sample is a valid urine sample. Reflects recent use. How long a drug can be found in urine depends on the drug, the dose, how often it was used and the person.

When to talk to a clinician

A drug screen result on its own rarely needs urgent care. Talk with the clinician who ordered it about what it means. If you or someone with you has trouble breathing, chest pain, confusion, a seizure, or can't be woken, call 911 or your local emergency number.

Questions you could ask

  • Which drugs are on this panel, and which ones I take might not be detected?
  • Was my sample sent for a confirmation test?
  • Could any medicine, supplement or food I take explain this result?
  • What cutoff did the lab use for this drug?

Questions people ask

Does a positive screen mean I took the drug?

Not always. A screen is a first look. It can react to look-alike medicines and some foods, so a positive result is called presumptive. A confirmation test with mass spectrometry is more exact and can name the specific drug.

Why did two labs give different results on my sample?

Each lab and program picks its own cutoffs and its own assay. A drug level just above one cutoff can fall below another. Published fentanyl screens, for example, use cutoffs from about 1 to 5 ng/mL.

Will an opiate test find fentanyl or methadone?

No. The CDC notes that a standard opiate screen does not detect synthetic opioids such as fentanyl or methadone. They need their own tests, so check which drugs your panel covers.

Show the science and sources

For clinicians and researchers

The first test is usually an immunoassay (enzyme, fluorescence or lateral-flow), calibrated to one analyte per drug class and read against a cutoff; the confirmatory test is GC-MS or LC-MS/MS. Cutoffs are set by the lab or program. The HHS federal workplace urine panel uses these initial cutoffs: marijuana metabolite 50 ng/mL, cocaine metabolite (benzoylecgonine) 150, codeine/morphine 2,000, hydrocodone/hydromorphone 300, oxycodone/oxymorphone 100, 6-acetylmorphine 10, phencyclidine 25, fentanyl 1, amphetamine/methamphetamine 500 and MDMA/MDA 500 ng/mL, plus separate confirmatory cutoffs that differ by drug (for example, 15 ng/mL for the marijuana metabolite and 4,000 ng/mL for morphine). Methadone is not on that federal panel. Clinical panels differ: one published point-of-care panel used methadone 200, opiates 100, benzodiazepines 150 and tricyclic antidepressants 300 ng/mL, and added fentanyl at 1 ng/mL later. In federal workplace testing, specimen validity rules say a urine sample is reported as dilute when creatinine is at least 2 but under 20 mg/dL and specific gravity is above 1.0010 but under 1.0030, and as substituted when creatinine is under 2 mg/dL and specific gravity is 1.0010 or lower or 1.0200 or higher; clinical labs may use their own dilute limits. The CDC 2022 opioid guideline advises using confirmatory testing when results inform major decisions, when a specific opioid or drug within a class must be identified, or when an unexpected screen result needs to be confirmed. It also notes that an opiate immunoassay detects morphine (from morphine, codeine or heroin) but not synthetic opioids such as fentanyl or methadone.

LOINC 69739-1 (primary), 87428-9, 65750-2. Specimen: urine.

Sources

  1. Mandatory Guidelines for Federal Workplace Drug Testing Programs: Authorized Testing Panels (91 FR 12308), HHS / SAMHSA, via the Federal Register (2026)
  2. Mandatory Guidelines for Federal Workplace Drug Testing Programs Using Urine (88 FR 70768), HHS / SAMHSA, via the Federal Register (2023)
  3. CDC Clinical Practice Guideline for Prescribing Opioids for Pain, United States, 2022, MMWR Recommendations and Reports (CDC) (2022)
  4. Drug Testing (MedlinePlus Medical Test), MedlinePlus, U.S. National Library of Medicine
  5. False-positive interferences of common urine drug screen immunoassays: a review, Journal of Analytical Toxicology (2014)
  6. Abnormal Urine Drug Screens in Pregnancy: Opportunity for Laboratory Stewardship, EJIFCC (2025)
  7. Performance of a Norfentanyl Immunoassay in Specimens with Low Concentrations of Fentanyl and/or Norfentanyl, Journal of Applied Laboratory Medicine (2024)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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