Drug testing a common tool for everyone from employers to rehabilitation centers. Used to determine worthiness for a job, sobriety for those struggling with addiction, or even by medical professionals to guide a course of treatment, drug tests play a large role in society.
Historically, these tests have been performed using urine samples, hair samples, or, in a hospital setting, blood samples. However, there is an easier way: mouth swabs. Non-invasive, easier than collecting urine, far faster to process, mouth swabs are a highly effective way of testing for blood, DNA, and disease.
Both those using drugs and those ordering tests understandably want to know more about the opportunities and limitations of drug testing using mouth swabs.
Mouth Swab Testing for Common Drugs
Due to the ease of testing, mouth swabs are becoming far more common in drug testing. In a mouth swab, a standard cotton swab is rubbed on the inside of the cheek to collect biological material. These swabs are then processed in a lab for everything from genetic information to foreign substances in the saliva.
As with blood and urine testing, the appearance of drugs within the body is detectable on varying timelines depending on the substance in question. Like other testing alternatives, oral swabs largely look for metabolites of drugs; these are the chemicals left behind after the body has processed a particular substance.
Mouth swabs are generally screened using enzyme immunoassay technology. Any samples that test positive will the be tested again using more specific methods, which may include liquid chromatography, mass spectrometry, and mass spectrometry to confirm findings.
More colloquially known as meth, methamphetamine is a stimulant that causes euphoric effects and can be smoked, snorted, and ingested. Meth isn’t a natural substance; it is created in a makeshift lab using ingredients like acetone, hydrochloric acid, ammonia, and ephedrine. It lasts longer in the body than some similar drugs, like cocaine, with its byproducts peaking around 12 hours after use.
Using an oral swab, meth can be detected as soon as 10 minutes after use and is identifiable for up to four days later for heavy users. Meth’s detection window is generally longer using other testing forms, like blood or urine tests.
Marijuana, a drug derived from a plant that is now legal in several states, offers euphoric effects when smoked, ingested, snorted, or injected. Its life in the body is far longer than most standard substances, particularly for regular users, as THC metabolites are stored in fat cells and slowly released into the bloodstream. For the average person, fat cells tend to linger, leading to detection windows as long as six weeks via its metabolites via blood or urine testing.
Unlike urine tests, which tend to look for the metabolite THC-COOH, oral swab tests search for THC itself as this substance remains in the saliva before being metabolized within the body. Saliva tests can identify marijuana use within the last 24 hours, making it a leading choice for police officers and others looking for the confirmation of recent use.
A stimulant that is frequently snorted in its pure form or smoked or injected in an impure form known as crack, cocaine is a popular drug among individuals of many different income levels and social classes. The detection window for cocaine is generally quite short, with metabolites like benzoylecgonine and ecgonine methyl ester remaining in the body for around 48 hours.
Cocaine isn’t detected for long in any kind of drug test, with a mean of two to three days. This is true for saliva tests as well; an oral swab generally cannot detect the presence cocaine or its metabolites past 72 hours.
Heroin and Other Opiates
As the recent statistics on overdoses indicate, heroin is currently an epidemic in the United States and is presently used at unprecedented levels. As such, heroin, as well as other opiates like hydrocodone and fentanyl, are popular targets in drug testing. While there are too many analogs for every single one to be tested, most comprehensive drug panels now test for as many opioid substances as possible.
Opiates are not all made equal, so the amount of time they are present in the body can vary. In general, heroin and many other opiates are detectable for 24 to 36 hours in saliva, which is shorter than the presence in urine or hair tests. Some opiates, however, may be detectable for a longer period of time. OxyContin, for example, is an extended-release variation of oxycodone, and thus stays in the body for a longer window of time. Many forms of opiates on the street, particularly illegally developed pressed pills, can contain unknown components and analogs, leading to more ambiguity in testing time.
Benzodiazepines, colloquially known as benzos, are used legitimately for numerous medical reasons, including addressing anxiety, insomnia, seizures, restless leg syndrome, Tourettes, and migraines. However, when used inappropriately, benzos can be highly addictive, leading to irresponsible use.
Due to the regular abuse of drugs like Xanax, a common anti-anxiety medication, benzodiazepines are frequently included in specialized drug panels. However, as the term benzodiazepine is a class of drug, there are numerous different substances that fall into this category and detection can vary greatly.
In general, benzodiazepines can be detected longer in saliva than via other testing methods, but the duration can vary greatly based on the drug in question. For example, the metabolites of diazepam, nordiazepam, temazepam, and oxazepam, can yield detection up to 10 days after use as diazepam is a long-acting benzo. An intermediate-acting benzodiazepine like lorazepam is only detectable for around five days due to the increased speed in which the body metabolizes the present substance.
Also known as ecstacy or Molly, methylenedioxy-methamphetamine is a common rave drug that is popular on college campuses and at parties. Due to its common use, it is often included in a standard six-panel drug screening and can be detected in blood, urine, and and saliva tests.
MDMA is screened using its metabolites, 3,4-methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxymethamphetamine (HMMA), and 4-hydroxy-3-methoxyamphetamine (HMA), and can be noted in the saliva from around one hour after use. The life of MDMA in saliva is shorter than other testing methods, however; most traces will be gone within 24 hours.
Alcohol is not a part of most blood or urine tests due to the rate at which it is metabolized in the body. Unless alcohol is consumed immediately prior to a test, the average individual will be able to have a few drinks the night before, sleep it off, and test negative by the next morning. Saliva tests, however, do have a longer window and may be able to detect alcohol after the body has metabolized the ethanol. Alcohol can be identified in a saliva test for six to 12 hours, long after the body will have metabolized several drinks.
While labs are ultimately permitted to devise their own thresholds for non-federal employee testing, most facilities adhere to the the Substance Abuse and Mental Health Services Administration’s proposed guidelines. For oral testing, these include:
- THC (marijuana): 4 nanogram per milliliter for initial testing and 2 ng/mL for confirmatory testing
- Benzoylecgonine (cocaine): 15 ng/mL for initial testing and 8 ng/mL for confirmatory testing
- 6-acetylmorphine (heroin): 3 ng/mL for initial testing and 2 ng/mL for confirmatory testing
- Amphetamine/Methamphetamine (meth): 25 ng/mL for initial testing and 15 ng/mL for confirmatory testing
- Hydrocodone/Hydromorphone/Oxycodone/Oxymorphone (opiates): 30 ng/mL for initial testing and 15 ng/mL for confirmatory testing
- Methylenedioxymethamphetamine/Methylenedioxyamphetamine/ Methylenedioxyethylamphetamine (ecstasy): 25 ng/mL for initial testing and 15 ng/mL for confirmatory testing
Limitations in Oral Drug Testing
While oral drug testing does have numerous benefits, this does not mean there aren’t limitations that those employing oral swabs should keep in mind. The most notable disadvantage is the time drugs or their metabolites are present in saliva. The testing time range is generally far shorter than other methods, which means that users can simply take a few days off of using, test clean, and return to use. Further, medication use can potentially interfere with testing, leading to inconclusive results. For example, cough medicines with codeine could impact an opiate test. Some drugs cannot be identified in the saliva at all, leading to a lack of testing opportunity.
Some individuals do attempt to cheat oral drug tests, often by drinking a lot of water, chewing gum, eating mints, or using products sold specifically to interfere with the state of saliva. However, these efforts are usually unsuccessful. To prevent food substances from tampering with results, those undergoing testing are usually required to maintain an empty mouth for at least 10 minutes prior to testing. So far, no substances sold to tamper with saliva have proved effective.
Due to the non-invasive nature of testing, mouth swab tests offer compelling opportunities for drug, disease, and genetic testing for many different applications. As the process is easier and room for error is lower, oral testing is gradually replacing other forms of screening when opportunity allows.