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Mouth Swab Drug Test: An Employer’s Guide [2023]

saliva drug test employment

As an employer, you understand the importance of drug screens to maintain the safety of your workplace.

Employees who use drugs are likelier to be involved in workplace accidents, miss more days from work, and have higher turnover rates.

Did you know that workplace drug test failures reached a 16-year high in 2019 at 4.5%?

While the most commonly used drug screen type used by employers is a urine test, some employers choose saliva drug tests as an alternative.

Based on our experience conducting employment drug screens, we’ve written this guide about oral swab testing to use as a resource during the hiring process.

Let’s start now.

What is a Mouth Swab Drug Test?

A mouth swab drug test, or saliva drug test, is a screening tool that uses an applicant’s or employee’s saliva to detect substance use.

They’re also known as oral fluids drug tests, saliva drug tests, and oral swab tests.

Mouth swab drug tests aren’t the typical types of pre-employment drug screens companies use, but they are an easier-to-administer alternative to urine or blood tests.

Since the samples are collected under supervision, it’s also more difficult for an applicant or employee to tamper with them, and they are also less invasive than blood, urine, or hair tests.

Employers use mouth swab drug tests for many different types of screening, including pre-employment drug screens, random or periodic testing, reasonable suspicion drug tests, and post-accident screens.

While there are nearly instant-read oral saliva tests available on the market, most employers don’t use the instant screens because they’re not included in the mandatory oral fluid guidelines from the Substance Abuse and Mental Health Services Administration (SAMHSA).

Federal agencies are required to follow SAMHSA’s guidelines, and many private employers also choose to do so.

What are the Benefits of Mouth Swab Tests?

Oral swab tests offer the following benefits:

  • Non-invasive for applicants and employees
  • Fast, simple sample collection
  • Fast results
  • Affordable costs
  • Ability to detect very recent substance use
  • Tampering difficulty
  • Expands the detection window

Mouth swab tests are the most useful when you’re testing for recent substance use such as after a workplace accident.

What Can Be Detected in a Saliva Test?

Here are some of the substances that oral saliva tests check for.

1. Methamphetamine

Also known as meth, crystal, or crank, methamphetamine is a stimulant that can be injected, ingested, snorted, or smoked.

Meth is created in illicit labs using a variety of chemicals and remains in the body longer than other stimulants like cocaine. The byproducts of methamphetamine peak an average of 12 hours after ingestion.

With a mouth swab test, methamphetamine use can be detected in as little as 10 minutes after the donor last used it. It can be identified for as long as four days after its last use for regular meth users.

The detection window for methamphetamine is typically longer when you use other types of drug tests, including urine or blood tests.

2. Cocaine

Cocaine is another stimulant and is illegal. Unlike meth, cocaine is derived from the coca plant. .

In its pure form, cocaine users most often snort this substance. Cocaine is popular among people at all socio-economic levels.

The detection window for this drug on any type of drug test is short since the metabolites, including ecgonine methyl ester and benzoylecgonine, remain in the body for approximately 48 hours after use.

Swab tests can generally not detect cocaine or its metabolites if the last use was 72 or more hours before the screen.

3. Heroin and Other Opiates

The opioid epidemic has continued to be a problem across the U.S. In 2020, more than 68,000 people died from overdoses of heroin and other opiates.

Because of the dangers of illicit opioid abuse, heroin and opiates such as fentanyl and oxycodone are commonly included in employment drug screens.

Opiates can have varying detection windows, but they can generally be detected for 24 to 36 hours in a donor’s saliva. This detection window is shorter than the detectable presence when using hair or urine tests.

Some opiates can be detected for a longer period. For example, the use of extended-release oxycodone will remain detectable for a longer period.

Some opiates purchased on the street are adulterated and can contain unknown analogs and compounds, which can affect the detection window.


Methylenedioxy-methamphetamine or MDMA is commonly known as Molly or Ecstasy. This drug is a popular party drug among young people.

MDMA is frequently included in six-panel drug screens and can be detected with saliva, urine, or blood tests.

Drug tests check for MDMA’s metabolites, including 4-hydroxy-3-methoxymethamphetamine (HMMA), 3,4-methylenedioxyamphetamine (MDA), and 4-hydroxy-3-methoxyamphetamine (HMA). MDMA can be detected in saliva starting about an hour after use.

However, traces of this substance  can disappear from the saliva within 24 hours, which is shorter than the detection window using other testing methods.

5. Phencyclidine

Phencyclidine is also known as PCP or angel dust. This illicit drug is a hallucinogen but can also have stimulatory or anesthetic effects, depending on the amount taken.

PCP is manufactured in illicit labs and can cause users to exhibit violent or aggressive behavior.

On an oral saliva test, PCP can be detected in as little as five to 10 minutes after use. The detection window for PCP on a mouth swab test is up to three days.

6. Benzodiazepines

Benzodiazepines are prescription drugs with the street name “benzos”. They are prescribed to treat anxiety, seizures, insomnia, restless leg syndrome (RLS), migraines, and Tourette’s syndrome.

While benzodiazepines have recognized medical uses, they are also addictive and have the potential for abuse when taken improperly or without a prescription.

Applicants and employees who are prescribed benzodiazepines such as Xanax or Valium should tell the clinician administering the drug screen. Since these drugs are commonly abused, they are often included in drug panels.

There are many different types of benzodiazepines with varying detection windows, but they can generally be detected longer with oral swab tests than with other screening methods.

Long-acting benzodiazepines, including diazepam or oxazepam, are detectable for up to 10 days after use.

However, an intermediate benzodiazepine such as lorazepam can only be detected for up to five days because the body can metabolize it faster.

7. Marijuana

Marijuana is made up of buds from the cannabis plant and has both euphoric and hallucinogenic effects. It is legal to use for medical purposes in most states and recreational purposes in a minority of states.

People ingest marijuana through several different methods, including ingestion, smoking, or vaping.

It can be detected in the body for much longer than other substances because its metabolites are stored in fat cells and are slowly released.

Swab tests check for the presence of THC, which stays in the saliva before it is metabolized.

A mouth swab test can detect marijuana use within the last 24 hours.

With urine or blood tests, its metabolites can be detected for up to six weeks for heavy users.

How Are Mouth Swab Tests Done?

The administrator uses a long cotton swab to collect a saliva sample and cells from the inside of the donor’s cheek in a process that only takes a few seconds.

People who will provide samples are told not to eat or drink anything at least 10 minutes before the test.

Once the sample is collected, it will either be tested on-site or sent to the lab for processing. It will be analyzed for the presence of substances.

Substances in the donor’s system will have different detection windows. Oral tests check for drug metabolites that are left behind in the body after a substance has been metabolized.

Samples that test positive undergo confirmation tests using more sensitive methods, including gas chromatography, mass spectrometry, or liquid chromatography to identify the particular substances and their concentrations in the body.

What Are the Testing Criteria for Saliva Drug Tests?

While labs can determine the thresholds for the presence of drugs for non-federal employers, most follow the standards set by the proposed guidelines from SAMHSA.

Under these guidelines, the following minimum thresholds will be considered a positive saliva test:

  • Marijuana/THC – 4 ng/ml for initial tests; 2 ng/ml for confirmation tests
  • Cocaine – 15 ng/ml for initial tests; 8 ng/ml for confirmation tests
  • Heroin – 3 ng/ml for initial tests; 2 ng/ml for confirmation tests
  • Other opiates – 30 ng/ml for initial tests; 15 ng/ml for confirmation tests
  • Amphetamine/methamphetamine – 25 ng/ml for initial tests; 15 ng/ml for confirmation tests
  • MDMA – 25 ng/ml for initial tests; 15 ng/ml for confirmation tests
  • Phencyclidine (PCP) – 3 ng/ml for initial tests; 2 ng/ml for confirmation tests

Results above these thresholds on confirmation tests will be considered positives.

How Far Back Will a Mouth Swab Drug Test Go?

The detection window on oral swab tests lasts from 5  to 48 hours.

By contrast, urine tests can detect substances for up to four days, and blood tests can detect them for one to two days.

The drug detection window varies based on several factors, including the following:

  • Drug type
  • Quantity taken
  • Frequency of use
  • Use duration
  • Administration route and preparation
  • The donor’s metabolism
  • The testing method’s sensitivity

For example, a swab test will detect heroin (opioids) for about one hour while marijuana can be detected for up to 72 hours.

However, some types of drugs can be detected much longer, including:

Testing within the correct window is critical for obtaining accurate results since most substances are not detectable in saliva for very long.

As a result, saliva tests are typically used to identify recent or current use.

Heavy use might alter these windows. For example, a heavy cocaine user might have a detection window in saliva for as long as 10 days because of the cumulative effect of cocaine’s half-life.

How Long Do Results Take to Come Back?

The results from a mouth swab test can come back in  ten to fifteen minutes if you use instant on-site kits. However, some employers may have the specimens sent to a lab for analysis, which can take from one to three days.

If the initial test reveals a presumptive positive result, the sample will undergo confirmation testing by a medical review officer (MRO). The confirmatory test is more sensitive, and it might take an additional two to three days.

If it is positive and requires confirmatory testing, the entire process can take from three to six days before the results are returned.

How Accurate are Mouth Swab Drug Tests?

The accuracy of mouth swab drug tests depends on whether they are conducted properly.

In a study published in the Journal of Analytical Toxicology, researchers found that a mouth swab test followed by confirmation testing with liquid chromatography and mass spectroscopy had an accuracy rate of nearly 98%.

While properly conducted mouth swab tests followed by confirmation tests are highly accurate, the following factors can affect the accuracy of saliva screens:

  • Type of drug and its concentration
  • Test type used
  • The abilities and skill of the test administrator and the analysts in the testing facility
  • Whether the test is administered within the detection window for a specific drug
  • The testing device’s quality

The accuracy of a mouth swab test will also depend on whether you use an instant-read test or send the specimen to a lab for testing. Instant saliva drug test kits can be less accurate than lab testing.

Blood or urine screens are typically more accurate than mouth swab tests.

Mouth Swab Test Drug Testing Laws

If you intend to conduct drug testing of any type in the workplace, you must ensure that your testing policy complies with all relevant federal and state regulations.

Some of these laws are discussed below.

Federal Saliva Drug Testing Laws

Fair Credit Reporting Act

The Fair Credit Reporting Act (FCRA) is designed to protect the privacy of consumers in the information gathered and reported by consumer reporting agencies (CRAs) and used by employers to make hiring decisions.

The FCRA applies to drug testing when you use a third-party CRA to conduct your tests. If you do, you must notify all applicants and employees that you intend to conduct drug screens and get their written consent before you administer the drug screen.

If you decide to rely on the results of a drug screen to make an adverse employment decision, you must complete the adverse action process and provide the applicant or employee with a copy of the report.

You must also give the applicant or employee a copy of his or her rights under the FCRA.

Title VII of the Civil Rights Act of 1964

Title VII of the 1964 Civil Rights Act prohibits workplace discrimination based on the protected characteristics of applicants and employees.

To avoid violating Title VII, be consistent in your approach to test administration.

SAMHSA Guidelines for Federal Employers

As previously mentioned, federal employers are required to follow the SAMHSA guidelines for employment drug screens.

Instant-read oral fluid tests are not included in these guidelines, so federal employers cannot use them.

However, the federal SAMHSA guidelines don’t apply to private employers, so they can choose to use oral saliva tests unless they are prohibited from doing so under state laws.

Proposed Rule for DOT-Regulated Employers

While it’s not yet a law, the Department of Transportation recently published a proposed rule in the Federal Register on Feb. 28, 2023.

If this rule is adopted, it will allow DOT-regulated entities to perform oral fluid tests as an alternative to urine screens.

It will not do away with urine tests but will instead provide an additional option to transportation companies.

State Laws on Mouth Swab Drug Tests

The state laws on drug testing in general and on mouth swab drug tests vary widely. While most states allow saliva drug tests, a few don’t.

Here are a couple of examples of state laws.


In Vermont, under 21 V.S.A. § 513, employers are prohibited from extending conditional job offers based on a pre-employment drug screen.

However, employers can conduct probable cause drug tests for employees who are suspected of being under the influence.

If the employee returns a positive result, the employer cannot fire him or her as long as the employee attends and completes an employee assistance program.


Maine allows drug testing, but it must comply with the state’s restrictive drug testing statutes.

Employers must have a drug testing policy in place that complies with the state’s requirements and offer an employee assistance program certified by the Maine Department of Health.

iprospectcheck: Your Partner for Reliable, Employment Drug Testing Services

Employment drug screens can help to protect the safety of your workplace. If you intend to conduct employment drug screens, you must comply with all relevant federal and state laws and regulations. At iprospectcheck, our drug testing services fully comply with the FCRA and state regulations.

To learn more about our comprehensive employment screening services or to get a quote, contact us today: 888-509-1979

DISCLAIMER: The resources provided here are for educational purposes only and do not constitute legal advice. Consult your counsel if you have legal questions related to your specific practices and compliance with applicable laws.

Know Before You Hire

About the Author
Matthew J. Rodgers

Matthew J. Rodgers

Matthew J. Rodgers is a highly accomplished business executive with over 30 years of experience providing strategic vision and leadership to companies ranging from the fortune 500 to iprospectcheck, a company which he co-founded over a decade ago. Matthew is a valued consultant who is dedicated to helping companies create and implement efficient, cost effective and compliant employment screening programs. Matt has been a member of the Professional Background Screeners Association since 2009 . When not focused on iprospectcheck, he can be found spending time with his family, fly fishing, or occasionally running the wild rivers of the American west. A lifetime member of American Whitewater, Matt is passionate about protecting and restoring America’s whitewater rivers.