What is Oral Fluid Testing?

Oral fluid testing, which is also called saliva testing, is a method used to detect the presence of targeted substances in the test subject's oral fluid. Similar to a blood test, oral fluid testing detects substances that have been metabolized or produced by the body. For example, a salivary hormone test can be used to assess a person's adrenal function or melatonin production.

Oral fluid testing may also be used to detect the presence of certain diseases by determining if disease fighting antibodies are present in a fluid sample. Protein biomarkers for many diseases have been found in saliva samples. A more common oral fluid testing is used to detect drugs and alcohol. Substances that a person ingests, such as drugs or alcohol, can be detected in a saliva sample after they have been metabolized travel through the bloodstream.

What is Saliva Drug Testing?

Sometimes called saliva testing, oral fluid testing is widely used for drugs of abuse testing. Drug rehabilitation facility employees, members of law enforcement, and family court officials are all fields in which oral fluid drug testing may be used as part of a compliance, monitoring, or prevention program. In the workplace setting, saliva drug testing is often used to detect the use of drugs or alcohol by employees or prospective employees.

Methods of Oral Fluid Drug Testing

Oral fluid drug testing can be conducted on-site to provide nearly immediate results or a sample may be sent to a lab for deeper analysis. Unlike blood or urine testing, oral fluid testing is non-invasive. The sample is collected using either an absorbent mouth swab or by asking the test subject to spit into a collection container. A test subject can collect his or her own sample while under observation without significant privacy issues being raised. Additionally, this observable collection process makes it difficult for someone to adulterate or dilute their specimen, as can often happen with urine tests. (Learn more in "How to Avoid Adulteration in Employee Drug Testing".)

Laboratory-based oral fluid drug testing is considered the most accurate form of oral fluid drug testing. This method employs a two-step process to evaluate the saliva specimen. The first test is a drug-specific enzyme immunoassay (ELISA) test. In simplified terms, this test uses an enzyme that competes with the target drug to attach to a binder, usually a solid surface. If the target drug is present in a sample, it will take up the available binding sites leaving the enzyme unattached. Then, another substance that reacts with the enzymes is added to the test sample. This substance reacts with any unbound enzymes and produces a color change or other chemical signal, indicating a positive result.

Free Download: What Your Company's Drug and Alcohol Policy May Be Missing (and How to Get It Right)


If a positive result is detected using the immunoassay test, then a confirmation test is conducted using a more detailed process. The second level of testing uses a different type of analysis, either gas chromatography/mass spectrometry (GC/MS) or liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS). Chromatographic testing examines the substances in the test sample by examining them at a molecular level. This level of analysis allows lab technicians to identify the presence of specific drugs in a selected sample at very low threshold levels.

Recently, drug test manufacturers have begun offering point of care or point of collection (POC) tests that provide rapid on-site test results. POC testing may use a stationary device into which samples are inserted for analysis or a self-contained, single-use unit for detecting the presence of selected drugs or alcohol. These new, sophisticated POC tests use varying forms of immunoassay technology to yield preliminary test results in the field. (Learn more in "Three Types of Drug Testing: What Employers Should Know About Lab Testing, POCT, and Express to Lab Testing".)

Limitations on the Use of Oral Fluid Drug Testing

Both regulatory and practical limitations will affect how and when oral fluid drug testing is an effective choice for an employer's drug-free workplace program. Some of the most pressing limitations are described below.

Regulatory limitations:

In the United States, federal law limits the use of oral fluid testing in the workplace. Federal laws requires that all federal employees be tested for drug and alcohol abuse. Employees in private industries are also required to be tested if they hold so-called safety-sensitive positions, as defined by the Department of Transportation (DOT). (Learn more in "DOT vs. Non DOT Testing: What's the Difference?") Drug and alcohol testing conducted in compliance with these federal laws must comply with the Substance Abuse and Mental Health Service Administration Mandatory Guidelines for Federal Workplace Drug Testing Programs (SAMHSA).

As of January 2017, the SAMHSA does not permit the use of oral fluid testing for compliance with federal drug testing rules. However, plans are being considered for inclusion of such testing in the future. Additionally, other federal, state and local laws may govern when and how oral fluid drug testing may be used. In particular, any type of drug testing conducted by an employer must comply with Federal and State labor, privacy, disabilities, and civil rights laws. (Learn more in "State Drug Testing Laws: What Should Employers Know?")

Practical limitations:

As with all methods of drug testing, there are also variances in accuracy and reliability between different drugs being tested. Overall, laboratory based oral fluid drug testing is considered to be as accurate as other lab-based methods such as urine testing. (Learn more in "How accurate are oral fluid drug tests?") However, there are some limits and challenges specific to oral fluid drug testing.

First, oral fluid drug testing cannot detect drug use outside a limited detection window. It is best used as a vehicle for determining recent drug use by an employee. An oral fluid test can detect the presence of some substances in as little as 30 minutes after ingestion. This allows for quicker detection of a substance after exposure than a urine test. However, the total detection window for oral fluid testing of most drugs is small, usually 24 to 48 hours. In comparison, a urine test detection window for most drugs is 24 to 72 hours. For detecting past or long-term drug use, hair samples are considered the best indicator. (Learn more in "Oral Fluid, Urine, and Hair Testing: What's the Difference?")

Second, some individuals may not be able to produce enough saliva to present a viable specimen. Dry mouth syndrome caused by anxiety, lack of hydration, or other common conditions may prevent an adequate sample from being collected. Some medications can also interfere with a person’s ability to produce adequate saliva. Foods or liquids used to stimulate salivary production can have a short-term effect on the detected concentrations of some drugs. If a mouth rinse is used, or liquids or foods are consumed prior to testing, a delay may be necessary to ensure a valid sample is collected.

Oral Fluid Testing in the Workplace

Maintaining a drug and alcohol free workplace is an effective way to improve the health of your employees and the safety of your job site. As new technology develops, oral fluid testing is becoming an increasingly popular tool. The use of oral fluid drug testing eases many of the problems caused by other forms of testing and provides quick and accurate results for employers. Oral fluid drug tests can be ordered in panels that screen for federal covered drugs only, or in expanded panels that test for additional drugs of abuse. Alcohol screening tests are available as well.