The Dried-Spot Assay Did Not Include 11-Hydroxy-THC
The dried-spot method quantified THC and THC-COOH, but did not include the active metabolite 11-hydroxy-THC. Its omission was not a negative result for that metabolite in the participants.
Sensitivity constrained panel development
The authors explained that preliminary work did not achieve sufficient sensitivity for 11-hydroxy-THC at lower concentrations. They therefore did not include it in the reported method. This is a limitation of the analyte panel, rather than evidence that the metabolite was absent from the blood.
Unmeasured and undetected are different categories
A negative finding requires a test that actually addresses the compound under stated analytical limits. When an analyte was not included, the resulting dataset cannot establish its concentration, detection frequency or relationship to other cannabinoids. The successful THC and THC-COOH measurements do not fill that gap.
Panel completeness matters to the opinion
Identify the requested compound before relying on a report described broadly as cannabinoid testing. The paper supports its two-analyte method and specific paired-matrix comparisons, while leaving another relevant metabolite uncharacterized. It does not justify assigning a zero value to 11-hydroxy-THC, deriving a metabolic ratio involving it or treating the limited panel as a complete functional assessment of cannabis effects.
Related analysis: the study’s broader findings and limitations.
