What to Know About Mouth Swab Drug Tests

A mouth swab drug test is a screening tool that takes a saliva sample to detect certain substances in your system.

Mouth swab drug tests are used in various settings, such as workplaces and rehabilitation facilities. These tests are more cost-effective and less invasive than other drug tests, like samples of someone's hair, urine, blood, or sweat.

This article will explain how mouth swab drug tests work, what substances they can detect, how long it takes to get results, and more.

mouth swab drug test
Peter Dazeley / Getty Images.

How Does It Work?

A mouth swab drug test uses a long Q-tip with a sponge-like material to collect your saliva sample. It's done by sweeping the inside of the cheek or underneath the tongue. Either you or a test administrator will perform the swab.

A mouth swab drug test is brief, lasting only one to three minutes. Additionally, you do not need to prepare for the test in any way. You are typically asked not to eat or drink anything around 10 minutes before the test.

What Does It Test For?

Mouth swab drug tests can detect a variety of different substances, including:

If you or a loved one may be struggling with substance use disorder or addiction, call the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area. You are not alone.

How Accurate Is a Mouth Swab Drug Test?

If the mouth swab drug test is performed correctly, the test has an accuracy of 97.5%.

Factors Influencing Results

Research has shown that certain factors affect whether substances can be detected by a mouth swab drug tests. Eating or drinking within 10 to 15 minutes of the test, for instance, has been shown to interfere with results.

Other circumstances can also influence the accuracy of a saliva test. These include:

  • How much of the substance was consumed
  • Frequency of substance use
  • Quality of the drug (which can be affected if other substances were mixed with it)
  • Age
  • Liver and kidney health
  • Body mass and metabolism
  • Amount of water in the body

Detecting Substances After Use

Ultimately, the type of drug being tested for and when it was last used will contribute to whether you get a positive reading.

Marijuana can usually be detected via a mouth swab if you have used it within 24 hours. For opiates, the length of time varies.

Opiate  Time Detectable in Saliva
 Codeine 4 days
 Fentanyl 4 days
 Heroin  5 hours
 Hydrocodone 12 to 36 hours
 Methadone 2 days
 Morphine 4 days
 Oxycodone  2 days

How Long Does It Take to Get Results?

How long test results take from a mouth swab drug test will depend on the type of swab used. For example, some mouth swab drug tests will require lab analysis. Other drug test results can be interpreted on-site.

If your mouth swab drug test needs to be sent to a lab, you can expect results within 24 hours. For mouth swab drug tests that can be interpreted on-site, results can occur within minutes.

Legal Considerations

If you work in an industry related to transportation, national safety, or public safety, you may be required by law to undergo regular drug testing.

Depending on the regulations, those who test positive may be directed to substance abuse programs, which means you may not be immediately dismissed for having drugs in your saliva.

Laws for other industries vary by state. Testing oral fluids via a mouth swab is not allowed in Hawaii, Maine, Puerto Rico, and Vermont.

Benefits of Mouth Swab Drug Tests Over Other Types

There are several benefits to using a mouth swab drug test over other types of drug-screening processes, including urine tests and hair analysis. These benefits include:

  • It's non-invasive
  • It's more cost-effective
  • It can detect current usage
  • You'll get fast results
  • It's more difficult to tamper with results
  • It's quick and convenient


Mouth swab drug tests are a drug screening tool that uses saliva to detect various substances in your system. These tests are painless and quick, sometimes delivering results in minutes. Mouth swab tests are usually best for detecting recent drug use. Mouth swab drug tests are typically used to detect alcohol, amphetamines, cocaine, marijuana, opioids, and more.

A Word From Verywell

Some workplaces require drug screenings for employment. A mouth swab drug test is less invasive and cost-effective than other types of drug screening like collecting blood or saliva samples. If you are struggling with substance use, know you are not alone. Reach out to a healthcare provider to discuss resources and get help. Addiction is a disease and not your fault.

Frequently Asked Questions

  • How far back can a mouth swab test detect drugs?

    It depends on the substance. For example, marijuana can be detected by a mouth swab test 24 hours after use, but MDMA is undetectable 24 hours after use if it is the onsite American Drug Test-style test. The LC/MS/MS method is very sensitive and can further detect THC, THCA, and MDMA. Other factors will contribute, including frequency of drug use, how the drug was used, and the amount consumed.

  • What drugs can be detected with a mouth swab test?

    A variety of drugs can be detected using a mouth swab test. These substances include alcohol, amphetamines, barbiturates, benzodiazepines, cocaine, THC (marijuana), methamphetamine, opioids, and phencyclidine (PCP).

  • How accurate are mouth swab drug tests?

    Mouth swab drug tests are highly accurate. If a mouth swab drug test is administered correctly, this type of drug test has an accuracy of 97.5%.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Krotulski AJ, Mohr ALA, Friscia M, Logan BK. Field detection of drugs of abuse in oral fluid using the alereTM dds®2 mobile test system with confirmation by liquid chromatography tandem mass spectrometry(Lc–ms/ms)Journal of Analytical Toxicology. 2018;42(3):170-176. doi:10.1093/jat/bkx105

  3. Reichardt EM, Baldwin D, Osselton MD. Effects of oral fluid contamination on two oral fluid testing systems. Journal of Analytical Toxicology. 2013;37(4):246-249. doi:10.1093/jat/bkt009

  4. American Addiction Centers. How long do opiates stay in your system?

  5. How Long Does Marijuana (Weed) Stay in Your System? American Addictions Center.

  6. Substance Abuse and Mental Health Services Administration. Considerations for safety- and security-sensitive industries.

  7. Quest Diagnostic. Maps for drug testing laws.

By Molly Burford
Molly Burford is a mental health advocate and wellness book author with almost 10 years of experience in digital media.