EVIDENCE LIBRARY
Browse source-supported forensic toxicology guides in this subject area.
Oct 20, 2026
In 78 inpatients, urine cannabinoid immunoassay readings modestly tracked cannabis withdrawal, but creatinine-adjusted results were not significant overall.
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In 11,491 screened crash-injury patients, THC-only urine positives rose—but the modeled 2016 trend shift was nonsignificant and THC-only did not predict greater adjusted injury severity.
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An 18-person crossover found 7 reactive urine THC strips after swallowing a CBD-rich hemp cosmetic and none after topical use. No urine confirmation was performed.
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A 30-case study validated THC and metabolite testing in whole blood by QuEChERS GC–MS/MS. What the limits, recovery and driver specimens can—and cannot—prove.
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A 27-person primary study of CYP2C9/CYP2C19 and whole-blood THC after CBD-rich cannabis: null results, small repeat-use signals and forensic limits.
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A 130-driver primary study found no significant corrected simulator lane differences or THC-driving correlations 12–15 hours after smoking. See the limits.
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Original venous whole-blood study: bypass group had higher 10-minute ethanol and earlier peaks, but comparable later elimination. Evidence and forensic limits.
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A 44-person medical cannabis driving-simulator study found no significant group-by-time change across six outcomes; 18 completed both tests. Why urine positives do not establish impairment.
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Controlled n=24 crossover: oral THC 10 mg increased real-road SDLP (p=.02) but not simulator SDLP (p=.36); 20 mg affected both. Why this is not a proven diagnostic false negative.
Read guideOct 20, 2026
A 9-person hemp-oil hair study found cannabinoids after topical use. See what THC, CBD, CBN and metabolites do—and do not—prove in litigation.
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