Virginia Department of Forensic Science Releases Report on THC Blood Detection

The Virginia Department of Forensic Science (VDFS) recently released a report regarding its federal funded study to research reliable testing methods for detecting THC in blood.

DFS was originally granted $290,353 in 2020 by the Department of Justice’s National Institute of Justice. “The goal of this research project is to develop and validate an automated sample preparation technique for the quantitative evaluation of an expanded cannabinoid panel (CBD, CBN, THC, THC-A, CBC) in biological matrices…” stated the award description.

More than $1,188,390 million was available in total, and the sum was divided between a total of five projects. “The ever-changing climate of cannabis decriminalization and/or legalization has significantly impacted forensic laboratories and is anticipated to increase the caseload in forensic toxicology,” the description added. “In addition, products claiming to contain other cannabinoids, including cannabidiol and tetrahydrocannabinolic acid, have become widely available.”

Four years later, VDFS has released a 107-page report in February about its findings. The report shows the detailed process of separating THC metabolites, experimenting using different types of blood (bank blood, antemortem blood, postmortem blood, and also urine).

Ultimately, researchers developed a process to identify different cannabinoids. “Within the research project, a method was developed for the quantitative and qualitative evaluation of cannabinoids in biological matrices using supported liquid extraction,” the report stated. “The methodology employed LCMSMS [liquid chromatography with tandem mass spectrometry] with two analytical columns of different stationary phases to enhance the confirmation of cannabinoids.”

LCMSMS was used to help determine the slight differences between cannabinoids. “To enhance the selectivity of LCMSMS, a two-column chromatographic method was developed to enable additional confirmation regarding the identity of a compound,” researchers wrote. “Within the validations, the evaluation of interferences from other cannabinoids was critical in the assessment of the method and its validity.” 

VDFS was also awarded grant funds of $441,886 in 2023 with the intention of developing methods and tools to study other psychedelic compounds. “The detection of psychedelic compounds including psilocybin and N,N-dimethyltryptamine (DMT) poses an analytical challenge in biological specimens due to their rapid metabolism and known structural instability,” the award description stated. “An analytical workflow for the identification and quantitation of these compounds and their main metabolites needs to consider appropriate long term storage conditions and sample preparation parameters to minimize the implications associated with their inherent instability.”

This research effort was also one of five studies chosen to receive a portion $1,928,846, all with the intent of “identification of the most efficient, accurate, reliable, and cost-effective methods for the identification, analysis, and interpretation of physical evidence for criminal justice purposes.”

The discussions surrounding cannabis testing and how to accurately measure impairment have long been contested. One published in 2022 in Scientific Reports found evidence that neither THC detected in breath or in blood is a reliable way to indicate impairment. “Our findings are consistent with others who have shown that delta-9-THC can be detected in breath up to several days since last use,” researchers wrote. “Because the leading technologies for breath-based testing for recent cannabis use rely solely on the detection of delta-9-THC, this could potentially result in false positive test outcomes due to the presence of delta-9-THC in breath outside of the impairment window.”

President Joe Biden signed an infrastructure bill in November 2021, which included a provision that required the Department of Transportation to complete a report that includes recommendations on providing researchers with cannabis in order to study drivers under the influence of cannabis. That report was supposed to be completed by November 2023, but has not yet been delivered. 

Sen. John Hickenlooper reached out to the National Highway Traffic Safety Administration in November 2022 to receive an update on the report. “Preventing distracted or impaired driving is a key step towards the goal of reducing traffic fatalities and improving roadway safety. In 2021, nearly 43,000 fatalities occurred from motor vehicle crashes, which is among the highest annual totals in decade[s],” Hickenlooper wrote. “While the IIJA includes many laudable provisions to establish performance standards for crash avoidance technologies, evaluate monitoring systems to reduce distracted driving, and issue rules to detect a driver’s impaired status, many ambiguities around defining marijuana-impaired driving underscore the importance of clarifying this policy uncertainty.”

In October 2023, a study conducted by the University of Colorado Anshutz Medical Campus analyzed how to more accurately detect cannabis. “Since THC accumulates and lingers in fat tissue, daily cannabis users may maintain constant elevations of THC in the blood even long after the psychoactive effects abate,” said Michael Kosnett, MD, MPH. “There has been a lot of concern about whether the use of cannabis has been associated with an increased risk of motor vehicle crashes or accidents in the workplace.”

The research team measured whole blood THC and its metabolites, and calculated two blood cannabinoid molar metabolite ratios. Researchers determined a 98% specificity rate when examining if a person had consumed cannabis within 30 minutes.