Synthetic cannabinoids ('K2', 'Spice') are structurally diverse compounds sprayed onto plant material or dissolved for vaping to mimic THC. Unlike THC, which is a partial agonist, most are full CB-1/CB-2 agonists with greater potency and more severe effects, and they are often used specifically to evade THC testing.¹

Synthetic cannabinoids are imported as bulk powder and sprayed unevenly onto plant material, creating 'hot spots' that can deliver an unexpectedly high dose and cause seizures, psychosis, cardiovascular events, and renal injury.² They are commonly used by people under drug monitoring to avoid a positive THC result, because standard cannabinoid immunoassays do not detect them.³

Standard cannabinoid (THC) immunoassays do not detect synthetic cannabinoids; targeted LC-MS/MS is required. Panels measure specific parent compounds and metabolites (e.g., MDMB-4en-PINACA, 5F-MDMB-PICA, ADB-BUTINACA), but the market shifts quickly and a novel agent may not be covered.¹ Some metabolites, such as those of AB-FUBINACA, can persist for months, so detection does not always indicate recent use.¹

• Do not rely on THC immunoassays to detect synthetic cannabinoids; order targeted LC-MS/MS.
• Suspect synthetic cannabinoids when a monitored patient has cannabinoid-type toxicity but a negative THC test.³
• Interpret a positive cautiously: some metabolites persist for weeks to months and may not reflect recent use.¹
• Confirm the laboratory's current analyte menu, since new analogues appear frequently.
• Correlate with the clinical picture, given the risk of severe cardiovascular and neuropsychiatric effects.