Detection Windows for Drugs in Oral Fluid: Cannabinoids, Stimulants, and Opioids

Abstract

The objective of this research brief is to assess the literature on oral fluid detection times to address how long after a person uses a drug it can be detected in oral fluid, and what factors may influence detection times. As drug prevalence does not imply impairment, efforts to understand the proximity of drivers’ drug use in time may assist in better understanding and properly enforcing drug-impaired driving laws.

Introduction

In impaired driving enforcement, blood has traditionally been the preferred biological sample in determining the presence of drugs in drivers. However, collecting blood samples from drivers can be challenging, often resulting in delays impacting test results and noncompliance. The use of oral fluid as a matrix for the analysis of drugs is gaining popularity and an increasing number of research studies substantiate the correlation between drug concentrations in oral fluid and blood. Drugs may be deposited in oral fluid via ingestion (e.g., smoked or oral) and passive diffusion from blood into saliva. As a detection matrix, oral fluid has several advantages over blood and urine: collection is easy, noninvasive, and can be observed, limiting opportunities for adulteration. Oral fluid also can be collected at the roadside, close to the time of a suspected impaired driving offense. However, there is still much to be learned about the use of oral fluid especially as a detection matrix at the roadside. The objective of this research brief is to assess the literature on oral fluid detection times to address how long after a person uses a drug it can be detected in oral fluid, and what factors may influence detection times. As drug prevalence does not imply impairment, efforts to understand the proximity of drivers’ drug use in time may assist in better understanding and properly enforcing drug-impaired driving laws.

Key Findings

At some of the cutoffs considered in the examined studies, various analytes and metabolites were detectable in oral fluid for days and even weeks, long after the acute effects and impairment extend.

Methodology

A comprehensive search was carried out using the PubMed, Web of Science, Transport Research International Documentation, and Toxicology Literature Online (TOXLINE) databases for relevant scientific literature. The search targeted papers that combined certain key words related to (1) oral fluid (and variations thereof); (2) detection times or windows; and (3) particular drug types, classes or related metabolites. Articles were also required to be written in English and employ human subjects (vs. animals).

The initial search was conducted during the months of June to August 2018 and yielded over 1,800 articles. All titles and abstracts were reviewed for inclusion by three independent reviewers, based on the above criteria. Training on a subset of titles and articles was conducted to assess and improve inter-rater reliability. Manual filtering of the article list reduced the number of potentially relevant papers to approximately 150. A significant number of studies were omitted as they were not directly relevant to detection windows. Full text copies were obtained for those articles deemed relevant. Upon full text review, articles that did not contain information on detection times were excluded. Backward searching was also employed to identify additional relevant articles. Finally, articles were restricted to publication in the past 10 years in order to better reflect oral fluid technology currently in use.

For the final set of 29 articles, key information was distilled and entered into Detection Window Summary Tables by drug class. This information included drug type; route of administration; dose; analyte(s) and limit(s) of detection; collection device; analysis method; duration of oral fluid collection; minimum last detection time; median last detection time; maximum last detection time; participants’ frequency of use inclusion criteria; number of participants; and citation (source).

Results

As noted, key information was summarized in a series of Detection Window Summary Tables. These are available in Excel format as a resource to accompany this research brief. Individuals can sort and filter the information in the Summary Tables according to their needs or interests and are encouraged to consult the original references for further details.

Key findings and patterns regarding last detection times are highlighted in the research brief, with results from studies with similar dosing and routes of administration grouped where possible. The results are presented in terms of the median last detection time and the range (i.e., minimum and maximum) of last detection times among study participants with at least one positive result for the analyte(s) and limit(s) of detection of interest.

It is important to underscore that many factors can influence drug detection times in oral fluid. These include cutoffs, analytes, dose, route of administration, time since use, the amount of drug initially deposited in the mouth, oral fluid collection method, and collection device. Factors influencing detection times should be considered when interpreting test results and synthesizing across different studies.