What You Need to Know about Mouth Swab Testing

mouth swab

There are a number of ways to test an individual for drugs, but mouth swab testing may be one of the most popular methods due to its non-invasiveness. Unlike urine, blood or hair tests, mouth swab testing tends to be fast and convenient. Frequently used by police officers, healthcare workers and potential employers, mouth swab testing is often preferred by the people who are being tested.

Detection Windows for Drugs

It is important to realize that drugs will react with the body in different ways. When people reference a “detection window” for marijuana, for instance, they are referring to the amount of time marijuana — or its metabolites — can be found in saliva. In the case of marijuana, interestingly, the drug is only detectable in saliva for a few hours after consumption. Many are surprised to learn that methamphetamines, however, may be picked up by a mouth swab test three days after someone does meth.

Detection times – How far back will a mouth swab drug test go?

It’s important to note that these detection times can vary significantly depending on several factors, such as the individual’s metabolism, the amount and frequency of use, the purity of the substance, and the sensitivity of the test used.

SubstanceDetection Time in Saliva
Heroin1-2 days
Cocaine1-2 days
Cannabis24 hours to 3 days
Alcohol6-24 hours
MethadoneUp to 2 days
MorphineUp to 3 days
Amphetamines1-3 days
Opiates1-3 days


  • Heroin and morphine fall under the opiates category. Heroin metabolizes into morphine, which can extend the detection window slightly.
  • Cannabis detection times can vary the most among these substances. Regular users may have detectable amounts in their saliva for longer periods than occasional users.
  • Alcohol has the shortest detection window, and the exact time can vary depending on the amount consumed and individual metabolism rates.
  • Amphetamines include substances like methamphetamine and MDMA (ecstasy), which can be detectable within similar time frames.
  • Cocaine detection times can be influenced by the method of use and the dose.
  • Methadone, used in the treatment of opioid addiction, has a relatively long half-life, which contributes to its detection window.

These timelines are approximate and should be used as a general guide. The actual detection window can vary significantly from person to person.

drug test

An Overview of Mouth Swab Testing

In this article, we aim to explore what a mouth swab test actually is — and which drugs can be detected when your saliva is tested. With an eye on detection windows, we will investigate how mouth swabs — also called oral fluid drug testing — work on various substances. We will also look at some of the factors that may influence the length of time a drug may be identified in someone’s body.

How Does a Mouth Swab Drug Test Even Work?

Usually, when a healthcare professional administers a mouth swab, they will either place it under the tongue or put it between the gums and cheek. These are both good spots from which a good sample of saliva can be collected. If the sample is able to be analyzed on-site, then that analysis will usually be performed quickly. If, however, the lab is off-site, then the sample will be sent for analysis there. Lab workers will use either chromatography-mass spectrometry or enzyme immunoassay to determine the results. Mouth swabs can detect: heroin, cocaine, cannabis, alcohol, methadone, morphine, amphetamines, and opiates. Many in law enforcement do like the convenience of using a mouth swab. For example, a police officer can administer a mouth swab to someone they suspect of driving under the influence. Because a breathalyzer test can only pick up on alcohol, a mouth swab provides a much more thorough method of determining whether someone is intoxicated. It’s much easier than a blood draw and — unlike hair samples — is specifically targeted to determining whether or not someone has very recently used drugs.

The Science of Having Your Saliva Tested

When you take drugs, they will be present in your blood vessels, including even your smaller blood vessels; these are called capillaries. From the capillaries, the drugs — or their metabolites — will travel to the salivary glands, upon which point they make their way into your saliva. It’s important to note that pH levels can play a surprisingly big role in the way the drugs are processed. This depends upon whether your saliva pH is more acidic or alkaline. Saliva pH can be influenced by factors such as your diet and even how much water you’ve imbibed on a particular day. The blood-saliva barrier is another big factor. Between those aforementioned capillaries and saliva glands, seemingly tiny concerns such as molecular size can make a large impact. Even your personal blood flow to the saliva glands can influence the results of a mouth swab.

The Effectiveness of Hair, Blood, Urine and Mouth Swab Drug Tests

When one is investigating recent drug use, mouth swabs can be highly effective. Hair tests, however, often cannot determine more recent usage. Many times, they only detect drugs after someone used over a week prior. The advantage of hair tests, though, is that they may be able to detect substances years after drug use. If a company is trying to find out whether a job applicant has used any illicit drugs in their past, a hair test is highly effective. Urine testing is often used, meanwhile, to see if a person has used drugs within the past week or so. Blood testing is also useful for this purpose, but it is invasive.

Comparing How Substances Perform on Mouth Swabs

Alcohol: Alcohol can be detected within minutes of use and can sometimes even show up on a mouth swab a day later. Within the range of 12 to 24 hours, if you have consumed a fair amount of alcohol, you can expect for it to show up on a mouth swab.

Cannabis: Cannabis can also be detected within a few minutes of use. However, with cannabis, results are more likely to reflect use within the past day or two. Anything up to 48 hours is likely to be picked up by the test. For those who are frequent marijuana users, the test may pick up use from prior to 48 hours due to the omnipresent THC.

Cocaine: The sweet spot for finding cocaine on a mouth swab is also around 24 to 48 hours after usage, although it can also be detected within an hour of use.

Opiates: Perhaps it won’t come as a surprise that cocaine’s cousins — morphine and heroin — can also be easily detected around the mark of one day to two days.

Methamphetamines: Meth can also be easily detected within 24 to 48 hours, and some tests will pick up on the substance within minutes after usage.

Factors Influencing Detection Windows

There are a number of factors that can influence detection of drugs through mouth swabs. Even a person’s genetics can have an impact, so results may vary. As with any other medical test, it’s imperative to realize that there is always a possibility of a false positive.

Are You Worried About Mouth Swab Test Results?

Of course, the only way to ensure that you won’t keep having positive tests is to stop using drugs. This is so much easier often said than done. However, there is a peace of mind that comes with not having to stress about a drug test turning up positive. The team at Long Island Treatment Center works with those who are looking to turn their lives around. When negative drug tests are a necessity, this group truly excels at getting to the heart of whatever it is that is fueling your addiction — and works to help you correct it without shame or judgment.


  • Can my work give me a mouth swab drug test?
  • What can a mouth swab drug test test for?
  • How far back will a mouth swab drug test go?
  • What does it mean when my mouth swab drug test turns blue?



Reviewed for Medical & Clinical Accuracy by Long Island Treatment Center