Laboratories have typically measured drugs and metabolites using blood, serum or urine. But continued interest in using oral fluid as an alternative specimen has many laboratories wondering if now is the time for oral fluid to make its way onto their test menu.
Oral fluid testing is interesting because its use represents a noteworthy challenge for the laboratory, while at the same time providing several benefits to physicians and patients. The collection of oral fluid is minimally invasive, easier to observe than urine collections, and does not require trained personnel as is the case for blood or serum collection. But with any new matrix comes uncertainty about detection times, expected metabolites, required analytical sensitivity, and correlation of results with conventional sample types.
Today during an afternoon short course, Kent Lewandrowski, MD, Stacy Melanson, MD, PhD, and James Flood, PhD will review the advantages and disadvantages of oral fluid testing. Topics to discuss will include the technology needed to achieve the required analytical sensitivity and specificity, challenges with collection, comparison of oral fluid to urine, and how to interpret oral fluid results.
A quick Internet search for “oral fluid drug testing” yields over 1.1 million results—a clear demonstration of the interest in this topic. But despite the strong attention, many labs are still hesitant to move forward. This may be a result of the strong focus on the use of oral fluid in roadside testing for driving under the influence, an area that does not routinely involve the central laboratory.
But other areas such as workplace drug testing, pain management compliance, and even therapeutic drug monitoring have all seen continued interest in the use of oral fluid. Many laboratories remain cautious and are waiting until known limitations are dealt with, such as inconsistent collection, variable recoveries from collection devices, and broad immunoassay availability for automated analyzers. In addition, metabolite patterns and detection windows are different for oral fluid, making interpretation challenging for the laboratory. But recent trends in the use of mass spectrometry for high specificity screens as an alternative to conventional immunoassays may open the door for some laboratories to begin dipping their toes into oral fluid.
Clearly there remains a strong divide on the utility of oral fluid and if it will replace urine or other conventional matrices. But with a title like “Should I Add Oral Fluid Specimen Testing to My Urine Drug Program? What You Need to Know to Decide,” it’s no wonder that those registered are salivating over this opportunity.