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Urine Methamphetamine Screen

A yes-or-no urine test for methamphetamine. A positive is a first-step result that can have other causes, such as medicines, and is usually confirmed with a second test.

AI-verified against cited sources. Awaiting expert reviewAlso called METHLOINC 19554-5

What it is

This urine screen checks whether methamphetamine, or a chemical the test can't tell apart from it, is above a set cutoff. The result is negative or positive, not an amount. Most labs use an immunoassay, a test built on antibodies that can react to look-alike molecules. Methamphetamine is a stimulant. It is also a prescription medicine in one form, and another form (l-methamphetamine) is in some nasal decongestant inhalers sold in the US. The screen is used in medical care, treatment programs, workplace testing and legal settings.

Why it matters

A positive screen can affect care, work, school or legal decisions, so it helps to know it is only a first step. Immunoassays can react to look-alike substances, so labs treat a positive as presumptive and often confirm it with a more specific test. A negative result means the test did not find the substance at or above the lab's cutoff. It does not prove none was taken.

If it’s high

A positive screen means the test reacted at or above the lab's cutoff. By itself it can't tell methamphetamine use apart from a prescribed medicine, a nasal inhaler or a look-alike substance. A confirmation test can usually sort this out, and several other explanations are possible.

Common causes

  • A look-alike medicine. Amphetamine and methamphetamine screens are the ones most often reported to give false positives with common medicines, such as bupropion, trazodone and promethazine, and with the antibiotic moxifloxacin on one assay
  • A nasal decongestant inhaler that contains l-methamphetamine, mostly with heavy use
  • A prescribed medicine the body turns into methamphetamine, such as selegiline (a Parkinson's disease medicine) or benzphetamine (a weight-loss medicine)
  • Prescribed methamphetamine (d-methamphetamine)
  • Prescribed amphetamine medicines, which can carry trace methamphetamine that a sensitive test picks up
  • Methamphetamine use

What can help

  • Tell the clinician or reviewing physician about every prescription, over-the-counter medicine, inhaler and supplement you use
  • Ask whether the result will be confirmed with a more specific test, and whether the lab can tell the d- and l- forms of methamphetamine apart
  • If you are worried about your own substance 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
  • Medicines and inhalers that look like, contain or turn into methamphetamine
  • How long ago, how much and how often a substance 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
  • The cutoff decides the answer. The US federal workplace screen turns positive at 500 ng/mL of amphetamine/methamphetamine, ARUP's immunoassay panel uses 300 ng/mL for amphetamines, and Mayo's mass-spectrometry stimulant screen uses 100 ng/mL for methamphetamine, so one sample can be negative on one test and positive on another.
  • Look-alike molecules can trigger a false positive on an immunoassay. A 2010 review found false-positive drug screens, most often for amphetamine and methamphetamine, with many common medicines, including bupropion, trazodone and promethazine, and with a nonprescription nasal inhaler. The antibiotic moxifloxacin reacted with one amphetamine/methamphetamine assay at therapeutic urine levels.
  • Medicines that contain or turn into methamphetamine give a true positive for the substance: prescribed methamphetamine (Desoxyn), benzphetamine, famprofazone and selegiline, plus the l-methamphetamine in some nasal decongestant inhalers.
  • 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 a positive result, especially if you take any of the medicines listed above. If you or someone else has chest pain, trouble breathing, seizures, confusion, severe agitation or overheating after taking a stimulant, call 911 or your local emergency number.

Questions you could ask

  • Which cutoff did this test use?
  • Who will see this result, and how will it be used?
  • Will this result be confirmed with a more specific test?
  • Could any of my medicines or an over-the-counter inhaler explain this result?
  • Can the lab tell the d- and l- forms of methamphetamine apart?

Questions people ask

Does a positive screen mean I use methamphetamine?

Not on its own. A screen is a first step, and look-alike substances, some medicines and some nasal inhalers can cause a positive. A confirmation test, plus a review of the medicines you take, is how labs and clinicians sort it out.

Can a nasal decongestant inhaler cause a positive result?

Some US inhalers contain l-methamphetamine. In studies described in one paper, using an inhaler every 2 hours did not produce positive urine tests, but hourly use gave levels above 1,500 ng/mL in two people. A test that separates the d- and l- forms can help your clinician tell an inhaler from other sources.

My clinician prescribes an amphetamine medicine. Could that change this result?

It can. Prescribed amphetamine products can leave tiny traces of methamphetamine in urine, and some immunoassays react to amphetamine itself. Tell the person reviewing the result what you take. Labs can use ratios and the d- and l- forms to help interpret low levels.

Show the science and sources

For clinicians and researchers

Screening is usually a homogeneous immunoassay calibrated for amphetamine/methamphetamine, and the cutoff belongs to the lab. The HHS federal workplace urine panel (effective February 2024) uses a 500 ng/mL initial cutoff for amphetamine/methamphetamine and 250 ng/mL confirmatory cutoffs for each of amphetamine and methamphetamine. ARUP's clinical immunoassay panel uses 300 ng/mL for amphetamines and reflexes positives to mass-spectrometry confirmation. Mayo's LC-MS/MS stimulant screen reports methamphetamine at 100 ng/mL. HHS-certified labs may determine d and l stereoisomers for the medical review officer. Methamphetamine is mostly excreted unchanged, with under 10% as amphetamine. d-Methamphetamine comes from prescribed methamphetamine and from benzphetamine and famprofazone metabolism. l-Methamphetamine comes from selegiline metabolism and nasal inhalers. One published interpretation reads more than 20% d-isomer as suggesting illicit use or a d-methamphetamine source, and less than 20% d as fitting an inhaler or selegiline (earlier work, as summarized in Contella 2025). In a dosing study of an l-methamphetamine inhaler, urinary excretion peaked 12 to 24 hours after dosing began (Mendelson 2008). That paper also cites an earlier study (Poklis 1995) in which use every 2 hours gave no positive urine tests, while hourly use gave 1,530 and 1,560 ng/mL in two subjects. Trace methamphetamine in people prescribed amphetamine can be a manufacturing impurity, and labs may use a methamphetamine-to-amphetamine ratio and chiral analysis to judge it. Immunoassay cross-reactivity is assay specific: moxifloxacin reacted with the Abbott MULTIGENT amphetamine/methamphetamine assay (Colby 2019). Immunoassay positives are considered presumptive until confirmed by a second, independent method (Saitman 2014).

LOINC 19554-5 (primary), 113785-0, 3779-6, 19555-2, 113784-3. 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. Urine methamphetamine-to-amphetamine ratio by LC-MS/MS to differentiate methamphetamine use from pharmaceutical impurity in patients prescribed amphetamine, Journal of Mass Spectrometry and Advances in the Clinical Laboratory 2025;37:49-55 (2025)
  6. The clinical pharmacology of intranasal l-methamphetamine, BMC Clinical Pharmacology 2008;8:4 (2008)
  7. Commonly prescribed medications and potential false-positive urine drug screens, American Journal of Health-System Pharmacy 2010;67(16):1344-1350 (2010)
  8. Commonly used fluoroquinolones cross-react with urine drug screens for opiates, buprenorphine, and amphetamines, Clinical Biochemistry 2019;68:50-54 (2019)
  9. False-positive interferences of common urine drug screen immunoassays: a review, Journal of Analytical Toxicology 2014;38(7):387-396 (2014)
  10. LOINC codes verified with the NLM Clinical Tables LOINC search, U.S. National Library of Medicine

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

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