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By David J. Kuntz, PhD

The cornerstone for marijuana testing has been the detection of Δ9-THC in oral fluids, or its metabolite, Δ9-THCA, in urine. Under federal and non-regulated drug policies, Δ9-THCA metabolite is the only reportable metabolite. Specifically identifying Δ9-THCA as the prohibited cannabinoid has created an opportunity for marijuana chemists to create alternative cannabinoids with similar effects to avoid reporting a positive result.

Δ8-THC is one of the naturally occurring cannabinoids found in very low levels in cannabis plants. It was never considered a cannabinoid of concern, although the psychological effects are very similar to Δ9-THC. Both Δ8-THC and Δ9-THC have interactions at the CB1 receptor in the brain which creates the psychological high associated with marijuana use. Another naturally occurring cannabinoid, cannabidiol (CBD), is widely used by the public for its reported benefits for the treatment for chronic pain, anxiety, neurological diseases, GI disorders and many more medical conditions. CBD interacts with the CB2 receptor which primarily affects systems other than the brain.

Marijuana confirmation testing began to change around 2018 whenever marijuana chemists began creating Δ8-THC. Strong acids cause the chemical conversion of CBD into Δ8-THC, or Δ9-THC into Δ8-THC. The acids trigger the CBD ring structure to close to create THC, and they can move a double bond in the ring to convert Δ9-THC to Δ8-THC (see figures below). These new Δ8-THC products are available as edibles and included in vape pens sold through CBD shops, gas stations, and convenience stores. This was all done to circumvent the drug testing programs as Δ8-THC is not a reportable analyte for oral fluids or urine.

The legality of Δ8-THC is under review at the federal level. Sellers of Δ8-THC products are claiming that it came from hemp, which by definition has < 0.3% THC. The federal counter argument to this is that the Hemp Farm Bill did not allow for the conversion of CBD to other cannabinoid products. This argument is being debated at state and federal levels as tremendous economics are involved.

The introduction of Δ8-THC has had a major impact to laboratory testing. As an isomer, it is a minor variation of Δ9-THC. Individuals ingesting Δ8-THC products will test positive using the immunoassay screening tests. In confirmation testing using mass spectrometry, the two compounds are similar and need to be resolved from each other to allow the laboratory to make the forensic identification that is required in drug testing. It requires more instrument time and additional methods to make this happen. In work performed at CRL, individuals using large amounts of Δ8-THC as a replacement for traditional marijuana can be identified in the laboratory. The problem for these individuals is that Δ8-THC products are not pure and various amounts of Δ9-THC remain from the chemical conversion.

At the beginning of the drug program, CRL typically did not see any existence of Δ8-THC in confirmation testing of marijuana screen positives. By 2018, we started to see a Δ8-THC presence around 4% in samples that had screened positive for marijuana, which continually increased to 20% by 2022. Some samples had thousands of ng/mL of Δ8-THC metabolites. We found similar rates in oral fluids. Δ8-THC in oral fluid presented the same analytical challenge as urine with problems of interference with Δ9-THC, which prevented the laboratory from meeting all forensic testing requirements. The laboratory had to validate new analytical methods for oral fluid and urine confirmation testing to report appropriately.

The national trend to accept Δ9-THC for recreational and medical purposes has been increasing over the years. The sale of Δ8-THC is approved by most states, but some states have not approved Δ8-THC and are more tolerant to the approval and use of marijuana. Since Δ8-THC has most of the same effects as marijuana, its use is being carefully reviewed at the federal level as to whether Δ8-THC products should be prohibited for the federal drug program. Although individuals claim slightly less effects when using Δ8-THC, the impairment aspects have not been well studied. It still creates the same risk as traditional marijuana for operators of trucks, planes, or cars.

Changes to the THC molecule did not stop at Δ8-THC. Other variants are now available such as Δ10-THC, and HHC (Hexahydrocannbinoid) for the treatment of insomnia and inflammation. Another variant, THCP (Tetrahydocannbiphorol), is 33 times more potent than THC. THC-O-Acetate is 3 times stronger than THC and claims to provide an introspective effect, much like LSD. THCV (Tetrahydrocannabivarin) is yet another variant which is used for the treatment of Parkinson’s and epilepsy and is also reported to suppress hunger. All of these products are on store shelves as edibles and vapes.

Marijuana use is changing quickly with these alternative products which are rapidly taking the shelf space that CBD products occupied a couple of years ago. All of these products are detectable at the screening step in the laboratory which makes their reporting much more efficient. With the general acceptance of marijuana across the country, the federal government is still reviewing the legal status of the marijuana variants created by chemists. That decision will greatly impact the testing for marijuana and perhaps dozens of future products created using marijuana.

Tags: CBD, Drug Testing, Marijuana Testing, THC, Δ10-THC, Δ8-THC, Δ9-THC