As the cannabis derivative delta-8-THC grows in popularity, it’s important for drug tests to be able to detect and differentiate it from delta-9-THC – the primary psychoactive ingredient in cannabis. Breaking research showcased at the 2022 AACC Annual Scientific Meeting & Clinical Lab Expo demonstrates that common drug testing methods can do just that.
Over the last few years, use of delta-8 has been rising in popularity in the U.S. for two reasons. The first is that it’s known for giving users a milder high than regular marijuana, and the second is that delta-8 is unregulated at the federal level, which means that it’s legal in most states where cannabis use is still banned. However, because delta-8 products are unregulated, many contain toxic manufacturing by-products that make it more dangerous than delta-9-THC. In light of this, testing for delta-8 is needed to discourage people from taking these contaminated products as a way to circumvent drug tests. Testing is also needed to monitor the spread of delta-8 and to inform public health efforts to craft better regulations for it.
With this in mind, a team of researchers led by Uttam Garg, PhD, of Children’s Mercy, Kansas City and the University of Missouri-Kansas City School of Medicine, conducted research to see if tests that detect delta-9-THC can also detect delta-8. To do this, Garg’s team spiked negative urine samples with various concentrations of delta-8 (10-50 ng/mL) and analyzed these samples with a standard approach for detecting cannabis use. First, they screened the samples with a commercial cannabinoid immunoassay, then they followed this with confirmatory testing using gas chromatography-mass spectrometry (GC-MS).
Garg’s team found that the cannabinoid immunoassay yielded positive results for all samples with delta-8 concentrations of 30 ng/mL and higher. The GC-MS method also identified delta-8. The latter is especially significant because delta-8 and delta-9-THC are very similar at a molecular level, but the GC-MS method was able to distinguish between them due to a difference in retention time. The researchers confirmed these findings in a patient sample containing delta-8.
“With our methods, we can detect both delta-8 and delta-9 isomers and distinguish delta-9 from delta-8,” Garg said. “If someone is using delta-8-THC, the immunoassay we are using and likely other immunoassays which are out on the market will detect it. Once an immunoassay positive sample has been identified, then you need a chromatographic method to separate delta-8 and delta-9 because they are very similar structurally. That’s what we did in our lab – we used immunoassay for initial screening and GC-MS to separate and distinguish the two compounds.”