Drug Toxicology Monitoring, Oral Fluid Testing

Oral fluid is the liquid material collected from within the oral cavity of the mouth and is comprised of saliva (from submandibular, sublingual, and parotid glands), gingival crevicular fluid (from between teeth and gums), cellular debris, bacteria, and food residues.

Oral fluid drug testing is an alternative to urine drug testing. Results are similar to those obtained from urine drug testing, but there are several important differences. First, drugs are detectable sooner in oral fluid than in urine. Drugs enter the bloodstream and are transported throughout the body. Once the blood reaches the salivary glands, drugs rapidly enter the oral fluid. This takes less time than the time taken for drugs to enter urine. Second, drugs are cleared from oral fluid faster than they are cleared from urine. Thus, the oral fluid “detection window” for some drugs such as cocaine and heroin can be as little as a few hours. However, most drugs remain detectable in oral fluid for 24 to 50 hours after ingestion.¹

Quest Diagnostics offers multiple options for oral fluid drug testing. These include:

• Multi-class drug panels for presumptive analysis with reflex to definitive confirmation and quantitation
• Single-class drug tests for presumptive analysis with reflex to definitive confirmation and quantitation 

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is used for both the presumptive analysis and the definitive confirmation and quantitation.

Drugs classes and compounds and assay cutoffs for detection are listed in the table that can be accessed here.

Drug testing in the clinical setting can provide information that improves patient care. The results of drug testing can often prompt important clinical discussions with patients. For example, absence of an expected drug could suggest poor adherence or diversion, whereas detection of a non-prescribed licit or illicit drug could raise concerns regarding substance misuse. Discrepancies between expected and actual results could also call attention to patient intolerance to medication side effect or potential medical factors affecting drug disposition.

Various sample types can be used for drug testing. Urine is the most widely used and well-established sample type at present and offers the broadest options for drug testing. However, urine-based drug testing has several potential drawbacks including inconvenience and patient embarrassment, sample integrity problems when collection is not observed, and lack of privacy when specimen collection must be observed.

The decision to use oral fluid drug testing should take into account the potential benefits and drawbacks of this matrix as they apply to individual clinical scenarios. The main advantage of oral fluid testing is the ease of observing sample collection, while the disadvantages relate to shorter drug detection windows, lower drug concentrations in the sample, and limited specimen volume.

The preferred specimen is 3 mL of random oral fluid collected in an Oral-Eze^® collection device.

Specimen stability is:

• Room temperature: 72 hours
• Refrigerated temperature: 7 days
• Frozen temperature: 30 days

Rejection criteria: Specimen submitted in a non-Oral-Eze^® collection device.

Negative results indicate absence of drug and/or metabolite or concentrations below the assay cutoff. Positive results indicate presence of the respective drug and/or metabolite. Detection of drug(s) or drug metabolite(s) suggests that the patient has taken the drug(s).

There is no correlation between the time of dose, the dose taken, and the concentration of drug and/or metabolite in the oral fluid.

Yes. Oral fluid drug testing is considered a clinical test; therefore, multiple clinical specimens from one patient may be placed in the same bag. However, specimens from another patient should be placed in a different bag.

If you have any questions regarding this information or require assistance with interpreting these drug test results, please contact a Quest Diagnostics toxicology specialist at 1-877-40-RX TOX (1-877-407-9869). Specialists are available to assist you Monday through Friday from 8am to 10pm ET.