A mouth swab drug test is used to check if you have substances in your system, such as alcohol, marijuana, or cocaine. The test is performed using an oral swab that collects a sample of saliva. Results can be returned within minutes with a relatively high level of accuracy.
Mouth swab drug tests can be used in a variety of settings, such as workplaces, probation offices, and rehabilitation facilities.
This article explains how a mouth swab drug test works, what substances they can detect, and what to expect if you are asked to undergo one. It also describes how long substances are detectable in your system and your legal rights if an oral drug test is requested.
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How Does a Mouth Swab Drug Test Work?
Most mouth swab drug tests check for multiple substances. The kit includes a small plastic receptacle with up to 12 test strips visibly seen on the front of the device. Inside the receptacle, attached to the lid, is an oral collection swab with a sponge tip.
To perform an on-site mouth swab drug test:
- The tester will check that you have not had any food or drink for at least 10 minutes before taking the test.
- The lip of the receptacle is removed to obtain the collection swab.
- You will be given the swab and asked to run the tip along your cheeks, gums, and tongue for up to three minutes.
- The tester will take the swab and place it back inside the receptacle.
- The swab will deliver saliva to each test strip. Color changes will indicate if the test is positive (meaning that the specific substance was detected) or negative (meaning that the specific substance was not detected).
Why You Can't Eat or Drink
Certain foods or drinks can change the pH (acid-base) level of saliva and can alter the test results, potentially causing a false positive or false negative result. This includes vinegar, citrus, bicarbonate, fruit juices, and salt.
Even chewing gum and mouthwash need to be avoided at least 10 minutes before the test to ensure that the results are not tainted.
When Is the Test Used?
Because the window of detection is relatively small, a mouth swab drug test is used on-site to determine if you recently used alcohol or an illegal substance.
Situations in which testing may be performed include:
- Pre-employment drug testing
- Probation drug testing
- Live-in drug rehabilitation facilities
- Random drug testing
- Return-to-duty drug testing (such as after a suspension)
- Post-accident drug testing
What Can It Test For?
Mouth swab drug tests can detect a variety of different substances, including:
- Alcohol
- Amphetamines (including crystal meth)
- Barbiturates
- Benzodiazepines
- Cocaine
- Gamma-hydroxybutyrate (GHB)
- Ketamine ("special K")
- Marijuana (THC)
- MDMA ("ecstasy")
- Methamphetamine
- Methadone
- Opiates (like morphine and heroin)
- Opioids (like hydrocodone, oxycodone, and fentanyl)
- Performance-enhancing drugs (like anabolic steroids)
- Phencyclidine (PCP)
- Rohypnol ("roofies")
How Accurate Is a Mouth Swab Drug Test?
If the mouth swab drug test is performed correctly, the test can be highly accurate, sporting a sensitivity of up to 100% and a specificity of 86% for certain drugs. (Sensitivity refers to the percentage of correct positive results, while specificity refers to the percentage of correct negative results.)
Even so, some drugs are not well detected by the current generation of tests. The drugs for which saliva-based tests are least accurate are benzodiazepines and amphetamines,
Factors Influencing Results
In addition to eating and drinking before the test, there are other factors that can influence the accuracy of saliva testing, such as:
- Your age (which can influence how quickly or slowly a drug is metabolized)
- Your liver or kidney function (which can increase or decrease how fast a drug leaves the system)
- How much of a substance you consumed (large doses vs. smaller doses)
- How frequently a substance is used (as certain drugs can accumulate in the system)
- The quality of the substance (as some drugs are "cut" with inactive fillers)
How Long Is a Drug Detectable?
There is a window by which a drug is detectable with an oral swab.
In many cases, a drug can be detected in saliva as early as one hour after a dose. Thereafter, substances like alcohol and cannabis can remain detectable from several hours to several days before gradually dropping to undetectable levels. The same is true for opiates/opioids.
| Drug | Detectable in saliva (estimated) |
|---|---|
| Alcohol | 12 to 24 hours |
| Cannabis/marijuana | 24 hours |
| Codeine | 4 days |
| Fentanyl | 4 days |
| Heroin | 5 hours |
| Hydrocodone | 12 to 36 hours |
| Methadone | 2 days |
| Morphine | 4 days |
| Oxycodone | 2 days |
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. These include jobs regulated by the Department of Transportation.
Depending on the regulations, people who test positive may be directed to a substance abuse program (which means you may not be immediately dismissed for having tested positive).
Laws for other industries vary by state. Testing oral fluids via a mouth swab is not allowed in Hawaii, Maine, Puerto Rico, and Vermont.
Most other states allow the use of oral swabs for employee drug testing, albeit with limitations and restrictions. To find out about the laws in your state, contact the American Civil Liberty Union (ACLU) at 212-549-2500.
Where to Find Help
If you or a loved one is struggling with an alcohol or substance use disorder, call the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helplineat1-800-662-4357for information on support and treatment facilities in your area. You are not alone.
Pros and Cons of Mouth Swab Drug Tests
There are several benefits to using a mouth swab drug test over other types of drug-screening processes, including urine tests and hair analyses:
- The tests are relatively inexpensive.
- They are quick and convenient.
- The tests can detect current usage.
- Rapid tests provide results in minutes.
- Rapid tests are difficult to cheat because the tester is there with you the entire time.
- There is no need for a private bathroom or gender-specific testers.
On the other hand, there are certain drawbacks to mouth swab drug tests:
- The window of detection can be small, making them less useful for probation or return-to-duty screening (since you can "clean up your act" several days beforehand).
- Some drugs, like benzodiazepines and amphetamines, can be harder to detect.
- For people whose jobs fall under Department of Transportation regulations (such as pilots), oral swab tests are not allowed to be the primary form of drug testing.
Summary
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.
10 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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By Molly Burford
Molly Burford is a mental health advocate and wellness book author with almost 10 years of experience in digital media.
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