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Oral Fluid: Is It the “Magic Loogie” of Drug Testing?

Team TFS
Team TFS

While the workplace compliance drug testing market continues to use testing techniques like immunoassays for initial testing and confirm results with mass spectrometry based technology, new matrices and alternative initial testing with HPLC mass spectrometry based techniques are solidifying their place in routine testing by way of regulatory changes and continued research by institutions such as NIDA.

Current Matrix Options for Compliance and Law Enforcement Drug Testing

While each testing technique has some limitation, the factors most testing programs consider are cost, accuracy, chain of custody requirements, confidentiality, possibility to take immediate decisions, minimize operator skill level, test portability, and low risk of test adulteration.

Urine-based testing represents the most commonly used matrix in drug screens. More than 55% of the current test approaches still utilize urine. Collection is relatively non-invasive, can be done on-site using newer products, and has a broad detection time window. Most testing labs focus on metabolites rather than the parent drug, which may indicate the presence of “use” weeks after original consumption.  Urine based testing does not indicate a true reflection of being under the influence, at the time of sampling. However, it’s still a low cost solution with a variety of preliminary drug screening test options available.

Blood-based testing represents greater than 30%; the second most commonly used matrix. Generally tests target the parent drug and comparative interpretation is easier to perform. Because highly trained personnel are needed to collect samples, no on-site testing is available.

Oral fluid-based testing represents less than 10% of the most commonly used matrices, but growing nearly twice as fast in volume year-over-year.  Oral fluid is considered the least invasive, can be collected at a crime scene, accredited testing facility or even a workplace, and studies have shown the potential to obtain equivalent results to blood test. It’s more frequently deployed to test for parent drugs but new studies show in combination with highly-selective detection systems, it can also be deployed to target metabolites, enabling the determination of use days or weeks prior.

History of Oral Fluid-based Drug Testing

In 2002, European ROadSIde Testing Assessment (ROSITA II) contract was signed. In 2004, Australian states began random roadside oral fluid testing. In 2005, ROSITA II report issued that oral fluid was not ready for forensic implementation, had limited sensitivity, was “operator” dependent and that oral fluid collection device OEMs has poor QC manufacturing controls. In 2006, the DRiving Under the Influence of Drugs (DRUID) programs began. In 2009, the ESTHER report evaluated oral fluid devices for harmonization and noted marketed collection devices had improved and roadside evaluation testing was again underway.

Various countries around the world (including Belgium, UK, Germany, France, Switzerland, Australia, Canada and select states in the US), have implemented oral fluid as a reasonable matrix for drug testing, particularly at roadside testing most notably to further deter drivers.

Future of Oral Fluid-based Laboratory Testing

In June 2011, SAMHSA (Federal Register Volume 76, Number 112) proposed oral fluid workplace testing.  SAMHSA need to answer such questions as:

  • What analytes should be measured in oral fluid for the initial and confirmatory tests?

  • What initial and confirmation cutoffs should be used for the oral fluid tests?

  • Should the oral fluid drug testing panel be expanded to include schedule II prescription medication?

In May 2015, HHS published two Federal Register Notices on:

  • Proposed revisions to the Mandatory Guidelines for Federal Workplace Drug Testing Programs using Urine (URMG); 94 FR 28101

  • Proposed Mandatory Guidelines for Federal Workplace Drug Testing Programs using Oral Fluid (OFMG); 94 FR 28054

In addition to requesting comments about drug testing additions for compounds (including oxycodone, oxymorphone, hydrocodone and hydromorphone) and lowering testing cutoff levels, they proposed the use of alternate laboratory test methodologies; LC based mass spectrometry technology, for initial testing; in addition to the traditional confirmation testing. This allows laboratories to implement cost-effective alternatives to immunoassay testing as long as they can achieve the requisite sensitivity, and accuracy.  As well as, calibrate with one or each analyte (depending on the technology) and can demonstrate the quantitative sum of the analytes must be based on the quantitative values for each analyte - and must be at or above the laboratory's LOQ.

No doubt new mass spectrometry based workflows, better automation and high-quality products will continue to advance the ability for labs to improve compliance testing.

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