Drug Testing

Oral Drug Test: Advantages and Disadvantages

An oral drug test, or mouth drug test, works by collecting and testing an individual’s saliva. The most popular and reliable test is the oral swab drug test, in which a sterile swab is placed between the cheek and lower jaw for about three minutes to absorb saliva. 

Employers turn to oral drug testing to ensure their employees are not using illegal drugs. There are also home kits parents can use to determine if their children are taking drugs or drinking alcohol. After collecting the sample and sealing it, it is then sent to a participating lab for testing and results.

Like any drug screen, there are pros and cons of oral swab drug tests. Reading about them can help you decide if this type of screening fits your needs.


Oral Drug Test Benefits 

The benefits of oral drug tests include noninvasive testing and rapid results for several substances. Mouth drug testing is easy to administer and also less expensive than more invasive urine screens and blood draws performed in laboratories. 

Oral tests accurately screen for alcohol and several common street drugs:

  • Amphetamines
  • Benzodiazepines
  • Cocaine
  • Heroin
  • THC/Marijuana*
  • Methamphetamines
  • Methadone
  • Opiates
  • Phencyclidine (Angel Dust)

* Employers in states where marijuana is permitted for recreational or medical use can still refuse to hire job applicants who test positive for its use. Federal employees are prohibited from using marijuana for any reason.

Many of these drugs are included in multi-drug test panels.


Oral Drug Tests Deliver Rapid Results

Mouth swab drug test detection times vary. Most show results within a day or even sooner, about the same as urine tests. Alcohol can be detected anywhere from six to 12 hours after collecting a saliva sample, and marijuana between 12 and 24 hours. Cocaine use will show up within a day of testing. Longer timeframes are needed for opiates and heroin (two to three days) and methamphetamines (two to four days). 

A few tests provide near-instant results as soon as a sample is added to a collection tube. Others produce results after about 10 minutes.


Alternative Drug Screen Tests are Invasive or Difficult for Patients

A mouth drug test is easier to take when compared to its alternatives: blood draws and urine tests.

  • Blood draws are invasive and may cause unnecessary pain. Even a skilled phlebotomist can have trouble finding a vein to draw blood and leave behind a bruised arm or hand.
  • Plenty of people have trouble producing a urine sample on demand, even after drinking copious amounts of water. Those with paruresis, or shy bladder, have an even more difficult time.

In addition, both blood and urine are classified as hazardous fluids and require special handling to prevent disease transmission.

In contrast, a mouth swab can be done at any time, without added physical or emotional stress. People who are taking and administering the test can be observed without undue violation of personal privacy. 


Oral Drug Test Drawbacks

The drawbacks to oral drug tests include limited drug detection timeframes and potential contamination from mishandling and the use of over-the-counter (OTC) medications.

  • Oral drug tests will only detect drugs used in the past few days, while blood draws and urine screens will detect metabolized drugs. This may not be sufficient for some employers, probation officers, and substance abuse treatment facilities.
  • People administering the test have to be careful to avoid contaminating the sample. They should be trained in proper handling techniques and determine that test subjects have not ingested medication, including OTC; mouthwash with ethyl alcohol; other liquids and food; tobacco; or chewing gum for at least 10 minutes prior to tests. 

Laboratory personnel, on the other hand, have completed specific training and certification for medical procedures that include administering drug screens. They know what questions to ask to determine if any substances are present that can compromise a drug screen. 

Ironically, some drugs cause dry mouth and interfere with producing a sufficient sample.


Can a Person Cheat on a Mouth Drug Test?

Assuming an oral drug test is properly administered, it is unlikely that a subject who has, in fact, recently used illicit drugs can beat it. This is probably why all articles on the topic “how to beat a saliva drug test recommend abstaining for a few days since the tests report on recent drug use.

Proper administration includes keeping a subject waiting for at least ten minutes before taking the test and making sure he or she does not ingest anything during that time. That last point can be challenging if there is a room full of people who are waiting to be tested.

There are no known adulterants that will compromise a saliva test administered in accordance with the manufacturer’s instructions. Saliva cannot be neutralized to affect test results. In addition, many tests include albumin, a protein that ensures the fluid collected and tested really is saliva.


Are Oral Drug Tests Better?

Oral tests look for recent drug use and might be the best scenario from a concerned subject’s point of view. Most can abstain for a few days. Urine tests, on the other hand, can detect use several days prior to testing. Some foods like poppy seeds can trigger false-positive urine screens for opioids three days after consuming bagels or pastries with them.

Positive Drug Test List of Causes: Medications and Food

How to dispute a false positive drug test, foods that cause false positive drug tests, medications that cause false positive drug tests, positive drug tests, what can cause a false positive for THC, false positive for PCP.

More and more people are required to undergo drug testing to obtain employment. It is a shock — and often an embarrassment — for someone who abstains from illegal drug use to discover that he or she has had a positive drug test. How did this happen? Most likely, the person recently took one of several medications that cause false positive drug test results. There are even certain foods that cause a false positive drug test.

What can a job candidate, or anyone else who needs to pass a drug screen, do to avoid triggering a false positive drug test? First, it is important to learn what medications and foods to avoid during the days leading up to a drug screen. It is also good to know how to dispute a false positive drug test.


Most Drug Tests Look for Evidence of Illicit Drug Use


Job candidates who are told they need to take a drug test should be aware that some prescription and over-the-counter (OTC) medications can alter drug test results. 

Most employment drug screening panels look for evidence of opiates, hallucinogenics, methamphetamines, PCP, or THC, the active ingredient in marijuana. And yet there are legitimate medications that can cause a false positive drug test for several medications.


Medical Marijuana and THC in Drug Screen

Probably the biggest concern is understanding what can cause false-positive results for THC. In part, that’s because edible medical marijuana has THC in amounts sufficient to show up on a drug screen. People who regularly take naproxen (found in ibuprofen) can also test positive for THC. These are common, over-the-counter drugs that are also prescribed in larger doses to control pain from surgery, childbirth, and injuries.


Many people diagnosed with GERD (gastroesophageal reflux disease) are prescribed medication from a class of drugs called proton pump inhibitors (PPIs). Not all patients need to take a PPI daily, but those who do can test positive for THC.


Common Pain, Sleep, and Cough Medications Might Trigger a False Positive for PCP


PCP,  or phencyclidine, is a strong hallucinogenic, or disassociative drug also known as angel dust. Its abuse became a serious problem in the 1970s and 1980s. Today, it is commonly laced into other street drugs including as much as 25% of non-medical marijuana. 

Several OTC pain relief medications and at least one prescription pain reliever are known to cause a false positive for PCP. Other medications that also trigger false positives include popular cough and sleep medications.

SNRI (serotonin-norepinephrine reuptake inhibitor) medications can return a false positive for PCP. These are prescription drugs that treat major depression, attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety, and a few other conditions. 

  • Ibuprofen (Motrin, Advil) and naproxen (Aleve)
  • Diphenhydramine, found in Benadryl and sleep medications like Tylenol PM and Advil PM
  • Tramadol, a prescription-only pain reliever
  • Venlafaxine, found in SNRIs antidepressants 
  • Dextromethorphan, the active ingredient in OTC cough syrups including Robitussin and Delsym
  • Doxylamine, found in OTC sleep medications like Unisom

Other Common Medications That Cause False Positive Drug Test Results


Several other medications can cause false-positive results for opiates, hallucinogenics, amphetamines, and methamphetamines. Here are a few of them:

  • Diphenhydramine (Benadryl) – methadone and PCP
  • Fluoxetine (Prozac) – amphetamine, methamphetamine, and LSD
  • Metformin (Glucophage) – amphetamine or methamphetamine.
  • Methylphenidate (Ritalin) – amphetamine, methamphetamine, and LSD
  • Pseudoephedrine (Sudafed) – amphetamine and methamphetamine
  • Sertraline (Zoloft) – benzodiazepines and LSD

Novocaine and Lidocaine will not cause a false positive test for cocaine. 

Foods that Cause False Positive Drug Test Results


A few foods are known to throw off drug test results, the most famous being poppy seeds baked into bagels and pastries. Many opiates are derived from poppy seeds including morphine and codeine.

Poppy seeds used in baked products are usually processed enough to avert any drug issue, although eating enough of them might cause a false-positive result. Raw seeds are generally inedible to most people. Quinine in tonic water is low enough that it is safe to be consumed in small amounts. But a drug test that detects high levels of it might lead to suspicion of opiate abuse because quinine is often used to cut heroin.

How to Dispute a False Positive Drug Test


Anyone who takes a drug test and is surprised by a positive result should first review any medications taken in the days before the test. It may be possible that something was omitted from the disclosure form.

Try to remember details about how the test was handled.

  • Could a specimen have been contaminated? 
  • Were staff administering the test and handling specimens wearing fresh clinical gloves? 
  • Did anyone appear ill? Coughing or sneezing around a specimen can contaminate it.
  • Was the facility clean? 
  • Was the test subject allowed to review the identification label attached to the specimen?

Some companies will allow strong candidates to retake a drug test. The best way to contest false-positive results is to reach out to your pharmacist and ask if prescription drugs and OTC medications you take on a regular basis can cause a positive drug test result. Ask if the pharmacist can provide written documentation to this effect and bring a copy to the test site. 

Remember, 15% of all drug tests return false-positive results. You aren’t alone in questioning a test’s accuracy. 

ScientiaDx partners with healthcare practitioners to improve the quality of patient care through drug testing. Medication monitoring can help identify possible illicit drug use and medication misuse. Reach out to our team to learn more about the services we provide.

6 Different Kinds of Drug Tests

Employers, parents, treatment providers, law enforcement, and criminal justice professionals have several types of drug screens to consider. Different drug tests are used to quickly obtain results or to test for a variety of substances including alcohol. Some screens look for recent drug use while others can detect substances taken several days or weeks prior to the test. 


Six Different Drug Testing Methods that Dominate the Current Market

There are six types of drug testing: oral, urine, blood, hair, perspiration, and breathalyzers. Traditionally, specimens were taken and analyzed in labs. Some tests allow consumers to collect noninvasive specimens and deliver near-instant analysis. Others like hair tests seal the specimen into containers that are sent to a lab.



  • Urine Screens: The Most Common Type of Drug Tests

Eight in 10 companies — about 90% of employers — require pre-employment drug screens and most rely on urine tests taken onsite, at a lab. Urine screens are also used by detox facilities to ensure patients are staying off drugs. 

A typical urine drug test panel looks for evidence of cocaine, marijuana, amphetamine, opiates, and alcohol. Some will also look for nicotine.


  • Saliva-Based Drug Test

Saliva testing looks for recent drug use and provides quick results. The test uses a mouth swab to collect saliva or requires the test subject to spit into a cup. It reveals alcohol, marijuana, cocaine, amphetamine, and methamphetamine use within the past few days, except for marijuana, which the test detects only for 10 hours after use.


  • Blood Test: The Drug Screen Gold Standard

Of all the drug testing methods, blood tests are the most accurate. They are also the only ones that are invasive and must be performed by trained phlebotomists and analyzed in a lab. 

Blood tests can detect alcohol use up to 24 hours after drinking. The test panels can also detect cocaine, marijuana, amphetamine, opiates, methamphetamines, and nicotine. Blood tests detect THC, the active ingredient in marijuana, weeks after use. 


  • Hair Follicle Drug Test

Hair testing is noninvasive and easy to obtain. The downside is that it does not show evidence of recent drug use, but rather historic drug use, up to 90 days ago to the most recent four or five. It tests for cocaine, marijuana, opiates, methamphetamine, and phencyclidine (PCP).

This test also takes longer to complete than other drug testing methods, particularly for subjects with long hair. At least 1.5” of hair is needed for testing. Every half-inch of hair reveals drug use within the last month. Only the newest hair is used. 


  • Perspiration Drug Detection Test

Perspiration is a new type of drug testing primarily used to monitor people in recovery or on probation/parole. This method screens for drugs through a patch applied to the subject’s skin and left on for 14 days. The patch collects perspiration and analyzes it for marijuana, cocaine, methamphetamines, LSD, and heroin.


  • Breathalyzer Testing

Breathalyzer testing for alcohol use is growing in popularity in the home market. New tests include smartphone apps for self-testing. Police use breathalyzers to provide on-the-spot testing for DUI. A suspect is asked to blow into a sterile tube attached to the breathalyzer detection device. 



Drug Tests Must Be Properly Administered

Even the most accurate blood test can be contaminated by improper handling that ends in an incorrect result. It’s important to have either a backup test or to permit a retest for subjects who request one, particularly if they take prescription drugs, which can cause false-positive test results.