Tox Tuesday: Oral fluid testing


Today there are several types of sample matrices used with forensic drug detection tests that are used around the world to identify the use and abuse of both prescription and illegal drugs.

Urine testing, for example, is one of the most commonly used and referred to methods, along with blood and hair testing. While each specific sample type provides its own set of benefits, none are without drawbacks. In order to combat some of the most common drawbacks however, the research and popularity around oral fluid testing has been expanding and showing that it can provide accurate results in a much easier and less intrusive way than other traditional testing methods.

Most oral fluid samples are used to test the same common drugs as urine, blood and hair tests and include testing for amphetamines, cocaine and metabolites, opioids such as morphine, methadone and heroin, and marijuana. Just like other tests, oral fluid tests can also be done for alcohol and prescription drugs such as pain killers.

According to a report from the U.S. Department of Justice, oral fluid, sometimes called “mixed saliva,” comes from three major and several minor salivary glands in a person’s mouth. Oral fluid contains many of the same enzymes found in blood, although far less complex, which makes its accuracy of results similar to that of a blood test.

The same report states that salivary glands that produce oral fluid have a high blood flow, so drugs migrate rapidly from the blood to the salivary glands within minutes. Because of this, oral fluid testing allows for the detection of drugs within hours after use. This is similar to blood testing, but unlike urine testing, which takes significantly longer and therefore cannot accurately tell if a person is currently using drugs at the time of test.

Along with the ability to know if someone has been using drugs within the last few hours, a report from by the National Association of Drug Court Professionals (NADCP), states oral fluid testing is done through an “absorptive device placed in the mouth,” making the collection process less invasive compared to urine collection. This process also eliminates many protocols and procedures involved in blood testing as it does not require the same type of medical professionals trained to handle blood.

While oral fluid testing provides quick results, some studies have shown they also offer a shorter “detection window,” compared to that of urine testing, and according to an online article, is the main contention between proponents of urine versus oral fluid testing.

For example, the U.S. Department of Justice report provides the following detection times for drugs in oral fluids, but also states that various factors including sensitivity of the test, the quantity or drugs consumed, the frequency of consumption, and the individual’s metabolism all need to be considered.

  • Amphetamines/methamphetamine: up to 50 hours.
  • Cocaine: up to 12-36 hours.
  • Opiates: up to 24 hours.
  • Marijuana: up to 24 hours.

These results can be compared to that of urine testing, which are stated in the report as follows:

  • Amphetamines/methamphetamine: up to 5 days.
  • Cocaine: up to 2 to 5 days (with exceptions for certain kidney disorders).
  • Opiates: up to 2 to 4 days.
  • Marijuana: up to 2 to 7 days, or up to 30 days after heavy use and/or in users with high body fat.

Based on an article from Medscape, oral fluid concentrations of basic drugs such as the amphetamines, cocaine and some opioids are similar or higher than those that show up in blood tests. In most cases, the same goes for tetrahydrocannabinol, or THC, the major component present in marijuana. However, according to one study, there is significant local absorption of the drug in the oral cavity which increases the concentrations of the drug for a period after use. This is not seen in blood or urine testing.

Known as a deposit effect, this can also occur for other drugs introduced into the body that allow local absorption, such as smoking of tobacco (nicotine), cocaine and amphetamines. Because of this, most experts agree that in order to get the most accurate results, oral fluid tests should be followed up with additional tests such as blood or urine.

Another positive aspect of oral fluid testing is that it takes only a few minutes and the collector observes the entire process from start to finish, thus eliminating attempts by the donor to cheat the test — something according to the report by the NADCP, many drug users have become highly competent in doing during urine tests.

“Drug abusers have detailed instructions on the Internet on how to beat drug tests accompanied by a supporting industry of products such as synthetic urine, adulterants and devices designed to fool urine collectors and confound specimen analysis.”

According to the article, adulterating oral fluid is “very difficult when collection is being directly observed,” and although there are new products being marketed that claim to give a “clean” oral fluids test, the likelihood of this happening is dramatically reduced when following the instructions of the test properly.”

The article also states that oral fluid testing eliminates “gender collection problems and shy bladder issues associated with urine collection. However, insufficient specimen volume can be a problem if the collection time is too short or the individual suffers from “dry mouth,” which can also be a side effect of drug use.

Regardless of the research available, according to Live Drug Free, urine testing today still remains the standard drug testing procedure and the only one that has regulated procedures by the United States Federal Government. However, many federal agencies permit and use oral fluid testing, such as the Federal Bureau of Prisons and U.S. Federal Probation. As stated in the article, the Federal Government has been in the process of considering alternative specimens to urine that include oral fluids for several years.

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