Oral fluid testing presents a quick and reliable way of testing for the recent use of many drugs and controlled substances — it’s particularly useful in the case of suspected cannabis use. Available as a lab-based and an instant test, oral fluid testing gives employers additional options for administering their drug testing protocol. (Learn more in Why Companies Are Moving Away From Urine Testing and Instant Oral Fluid Drug Tests 101).

However, any employer considering using oral fluid testing needs to be aware of the strengths and limitations of using any of these options.

Advantages of Oral Fluid Testing

Oral fluid testing offers three primary advantages over urine and blood testing.

1. Ease of sample collection
To collect a sample for oral fluid testing, all that’s required is to place a collection swab in the mouth against the cheek and wait a few minutes. With the testing kit, collection can happen anywhere and in front of a witness. It takes minimal training for the designated person to be able to collect a saliva sample.

2. Difficult to adulterate or swap samples
No reliable way of diluting or adulterating a saliva sample for oral fluid testing has been documented. And since the complete collection process can be witnessed, there’s no opportunity to swap samples and avoid detection that way.

3. Able to detect recent use
Oral fluid testing can detect drug ingestion as recently as 30-60 minutes ago. This is particularly useful when trying to determine drug use or impairment on-the-job.

Lab-based Oral Fluid Testing

As with any other lab-based testing protocol, once the saliva sample is collected it is sent to a lab to be processed. The lab processes the sample for the presence of drugs and drug metabolites. And, the lab provides both a drug screen report and a confirmation report.

Generally, lab-based tests are more sensitive than instant tests. This meant they tend to show more positive readings overall.

Using a lab that meets FDA standards for drug testing provides some assurance that the results are accurate. This is especially true of labs that require an FDA-cleared oral fluid collection device be used.

Since there aren’t federally-mandated standards for oral fluid testing, any employer using a lab to process oral fluid tests needs to completely understand the testing process used and how the results will be reported. The lab report will provide a numerical reading of any relevant drugs and metabolites found, but (depending on which drug is being tested for) it won’t necessarily offer an indication of whether the person was impaired.

Some states recognize test results that come from a lab-based oral fluid testing process, but not all. Any employer using this method needs to understand their state's laws and regulations and establish policies and procedures that comply with them.

Instant Oral Fluid Testing

Instant oral fluid testing is a self-contained test where the collection and processing of the sample happens on-site using a self-contained kit. This kind of kit might be called a rapid testing kit, rapid-result test kit, on-site test kit, or point of collection testing (POCT).

An instant oral fluid test may or may not include an FDA-cleared collection device. Since there are no legally-mandated standards for oral fluid tests, the sensitivity of the testing mechanism between oral fluid test (whether lab-based or instant) from different manufacturers can vary. Generally, instant tests are seen as less sensitive than lab-based tests.

As the kit allows for only one reading of the sample, instant oral fluid tests can only provide a screen and not a confirmation. Therefore, if the screen is positive, a second sample will need to be collected and sent to a lab for confirmation.

With an instant oral fluid test, the complete drug screen process can be done on-site and by existing staff, once they are properly trained. However, employers must have policies and procedures in place that ensure proper chain of possession and clearly identify who is responsible for determining the result when using an instant test.

Detecting THC with an Oral Fluid Test

Several characteristics of oral fluid tests make them attractive for detecting the recent use of cannabis and the presence of THC (the principal psychoactive ingredient in cannabis). However, there are limitations employers need to consider.

Oral fluid testing has been demonstrated to detect the presence of THC within an hour and up to 36 hours after use. This makes oral fluid tests good candidates to detect drug use on-the-job. Additionally, the fact that the collection process can be directly witnessed has increased confidence in these test results.

However, there is one very important factor that undermines the usefulness of oral fluid tests in this situation. There are no research-based or agreed-upon standards for the level of THC that corresponds with impairment. The test can measure how much THC is present, but it cannot determine if the person is impaired in any way.

Limitations of Oral Fluid Testing

The single most important limitation on using oral fluid testing in the workplace is the lack of regulatory recognition or standards. The federal government does not recognized oral fluid testing. And, while some states recognize oral fluid testing, others don’t even allow it in the workplace.

The result is a hodgepodge of legal and departmental barriers that make it difficult for any company to adopt the use of oral fluid testing, whether lab-based or instant, in their workplace.

A Complex Option

Oral fluid testing provides employers with another option when it comes to deciding which drug testing protocols to use. Given the current regulatory and legal limitations surrounding oral fluid testing, deciding to use oral fluid testing will add complexity to any employer’s drug testing program. It's an option that every employer will have to weigh and determine for themselves.