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Blood Test Tracker

Urine Opiates Screen

A yes-or-no urine test for opiates such as morphine and codeine. A positive is a first-step result and can come from prescribed medicine, poppy seed foods or some antibiotics.

AI-drafted. Awaiting verificationAlso called OPILOINC 19295-5

What it is

This urine screen checks for opiates, a group of pain medicines and drugs made from the opium poppy, mainly morphine and codeine. The result is negative or positive, not an amount. Heroin can show up too, because the body turns it into morphine. Most labs use an immunoassay, which reacts to morphine and, to different degrees, to similar molecules. It does not detect fentanyl or methadone and might miss oxycodone and buprenorphine. Those have their own tests. Screens are used in pain care, addiction treatment, workplace testing and emergency care.

Why it matters

Clinicians use this screen to check that a prescribed opioid is being taken as planned, to look into unexplained symptoms, and in addiction treatment. Because the test reacts to a whole group of molecules, a positive says little about which opioid it was. A negative does not rule out opioids the screen can't see. Unexpected results are best talked through with the clinician who ordered the test, who can ask for a more specific confirmation.

If it’s high

A positive screen means the test found opiates at or above the lab's cutoff. It can't tell which opiate it was or where it came from. Prescribed codeine or morphine, foods with poppy seeds and some antibiotics can all cause a positive, and so can non-prescribed opioid use. A more specific test can tell these apart.

Common causes

  • Foods made with poppy seeds
  • Prescribed codeine or morphine
  • Prescribed hydrocodone or hydromorphone, which some screens pick up to a variable degree (hydromorphone is also a breakdown product of hydrocodone)
  • Some antibiotics in the quinolone family, such as levofloxacin on at least one assay
  • Heroin or other non-prescribed opioid use

What can help

  • Tell the clinician or reviewing physician about every prescription and over-the-counter medicine you use and any poppy seed foods you ate in the days before the test
  • Ask whether a more specific confirmation test is available. It can tell morphine, codeine and others apart, and a separate heroin marker (6-acetylmorphine) can be added
  • If you are worried about your own opioid use, a clinician can talk through support options without judgment

What can affect your result

  • The lab's cutoff: the same sample can be negative on one test and positive on another
  • Which opioids the test covers: fentanyl, methadone, and often oxycodone and buprenorphine, need their own tests
  • Poppy seed foods and some antibiotics
  • How long ago, how much and how often an opioid was taken
  • Urine concentration: very dilute urine can push the level under the cutoff
  • Test type: immunoassay screens react to look-alikes, while mass spectrometry is more specific
  • Foods made with poppy seeds can show up as opiates. MedlinePlus advises avoiding them before a drug test.
  • Some antibiotics can react with the test. Levofloxacin reacted with one opiates immunoassay at levels seen during treatment, and other quinolones (ofloxacin, gatifloxacin) have been reported.
  • The cutoff decides the answer. The US federal workplace screen turns positive at 2,000 ng/mL for codeine/morphine, while ARUP's clinical immunoassay uses 300 ng/mL, so one sample can be negative on one test and positive on another.
  • The screen mainly detects morphine-like drugs. It does not detect synthetic opioids such as fentanyl or methadone and might miss semisynthetic ones such as oxycodone or buprenorphine, which have their own tests.
  • Very dilute urine can push the level under the cutoff and give a negative result.
  • A positive immunoassay is presumptive. Labs usually confirm it with a more specific method such as mass spectrometry.

A single random urine sample at any time of day. Some programs use an observed collection and check the sample for dilution or tampering. Reflects recent use. Drugs can be found from hours to several days or more after use, depending on the drug, the amount and how long it has been used.

When to talk to a clinician

A screen result is not an emergency by itself. Talk with your clinician about any result you did not expect. If someone is very sleepy and hard to wake, is breathing slowly or not at all, or has blue or gray lips, call 911 or your local emergency number right away. These can be signs of too much opioid.

Questions you could ask

  • Which cutoff did this test use?
  • If I take an opioid, which tests should be ordered to check it?
  • Which opiates does this test cover, and which does it miss?
  • Could a medicine I take, or something I ate, explain this result?
  • Should this be confirmed with a more specific test?

Questions people ask

Can poppy seeds really cause a positive opiate test?

Yes. MedlinePlus says to avoid foods with poppy seeds before a drug test because they can show up as opiates. Federal workplace programs do not accept poppy seed foods as a medical reason for a positive result.

I take oxycodone or fentanyl as prescribed. Why is my opiate screen negative?

The opiate screen mainly reacts to morphine-like drugs. It doesn't detect fentanyl or methadone and might not detect oxycodone or buprenorphine, so those have their own tests. A negative opiate screen doesn't mean you didn't take them.

Does a positive screen mean I used heroin?

No. The screen can't tell heroin from prescribed morphine or codeine. A separate heroin marker called 6-acetylmorphine (6-AM) can be tested, and your clinician can ask the lab for it.

Show the science and sources

For clinicians and researchers

Opiate immunoassays are generally calibrated to morphine and cross-react with codeine and, to varying degrees, with hydrocodone, hydromorphone and others. The HHS federal workplace urine panel (effective February 2024) lists separate initial tests: codeine/morphine at 2,000 ng/mL, hydrocodone/hydromorphone at 300 ng/mL, 6-acetylmorphine (a heroin marker) at 10 ng/mL and oxycodone/oxymorphone at 100 ng/mL. Clinical labs often use lower opiate cutoffs. ARUP's immunoassay uses 300 ng/mL, and Mayo's LC-MS/MS opioid screen reports many opioids and metabolites at 25 ng/mL. The CDC (2022) notes that a positive opiate immunoassay detects morphine, which might reflect morphine, codeine or heroin, but not synthetic opioids (fentanyl, methadone), and might not detect semisynthetic opioids (oxycodone, buprenorphine). A positive for one opioid can be a metabolite of another, such as hydromorphone from hydrocodone. Poppy seeds can produce codeine and morphine in urine, and federal workplace programs do not accept poppy seed foods as a legitimate medical explanation for a positive. Levofloxacin cross-reacted with the Abbott MULTIGENT opiates immunoassay at therapeutic urine concentrations, while it did not react with that vendor's oxycodone or methadone assays (Colby 2019). A 2010 review also lists quinolones (ofloxacin, gatifloxacin) among medicines with reported false-positive screens (Brahm 2010). Positive immunoassays are considered presumptive until confirmed by a second, independent technique (Saitman 2014). The CDC advises confirmatory testing when results will inform major decisions or an unexpected result has no other explanation, and says to discuss unexpected results with patients in a nonjudgmental way.

LOINC 19295-5 (primary), 113684-5, 3879-4, 8222-2, 18390-5. Specimen: urine.

Sources

  1. Mandatory Guidelines for Federal Workplace Drug Testing Programs Using Urine Specimens, 88 FR 70768, U.S. Department of Health and Human Services (SAMHSA), Federal Register (2023)
  2. Drug Panel 7, Urine - Screen with Reflex to Confirmation/Quantitation (test 0092184), ARUP Laboratories
  3. Controlled Substance Monitoring Hybrid Drug Profile, 20 Drug Classes, High-Resolution Mass Spectrometry and Immunoassay Screen, Random, Urine (CSMHU), Mayo Clinic Laboratories (catalog mirror at testcatalog.org)
  4. Drug Testing, MedlinePlus (U.S. National Library of Medicine)
  5. CDC Clinical Practice Guideline for Prescribing Opioids for Pain - United States, 2022, MMWR Recommendations and Reports 2022;71(3) (2022)
  6. Commonly used fluoroquinolones cross-react with urine drug screens for opiates, buprenorphine, and amphetamines, Clinical Biochemistry 2019;68:50-54 (2019)
  7. Commonly prescribed medications and potential false-positive urine drug screens, American Journal of Health-System Pharmacy 2010;67(16):1344-1350 (2010)
  8. False-positive interferences of common urine drug screen immunoassays: a review, Journal of Analytical Toxicology 2014;38(7):387-396 (2014)
  9. LOINC codes verified with the NLM Clinical Tables LOINC search, U.S. National Library of Medicine

AI-drafted. Awaiting verification. Last reviewed 2026-10-03. How we build and check these pages.

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