CBD-THC-Ratio (Metaboliten) im Urin

Urine, 5ml

With the increasing commercial availability and use of CBD-containing products, healthcare professionals are faced with the challenge of determining whether a positive cannabis drug test is attributable to the consumption of a CBD product or to the use of marijuana, medical THC, or other THC-containing products.

This issue is also of particular relevance for Switzerland, where CBD products containing less than 1% by weight of Δ9-THC may be legally marketed. This corresponds, for example, to a Δ9-THC content of up to 9.9 mg per gram of CBD cannabis flowers (cf. Federal Office of Public Health, FOPH, legislation on hemp and cannabis products, low-THC hemp, published online on 04 March 2025). Regardless of this, such products may also be obtained via the Internet, where it cannot be guaranteed that the actual active ingredient content corresponds to the declared values. Several studies have demonstrated elevated Δ9-THC concentrations in commercial CBD products (cf. Habel et al., Positive Cannabis-Urintests durch kommerzielle Cannabidiol-Produkte, Toxichem Krimtech 2020; 87(1):10).

To differentiate between types of consumption, Δ9-THC, CBD, and their metabolites (including glucuronides following enzymatic and alkaline hydrolysis of urine) are analytically determined. Subsequently, sum parameters are calculated and used to derive a quotient that serves as an auxiliary parameter for estimating the type of hemp products consumed (CBD-rich versus THC-rich products).

The resulting data are evaluated using a naïve Bayes classifier to determine probabilities for different consumption patterns (e.g., predominantly CBD use, combined CBD/THC use, THC-dominant use, or lack of interpretability). The classifier is based on published reference data and methodological approaches from studies [1–5].

Interpretation of the quotient is permissible only in conjunction with clinical and anamnestic information. In addition, the absolute concentrations of individual markers must be taken into account. In particular, at very high THC-COOH concentrations in urine (e.g., > 500 µg/L), the interpretative value of the quotient may be limited, as intensive or chronic THC use is likely in such cases (cf. Odell et al., Residual Cannabis Levels in Blood, Urine and Oral Fluid Following Heavy Cannabis Use, Forensic Science International 2015, doi:10.1016/j.forsciint.2015.01.026).

[1] M. M. Goggin & G. C. Janis, Using measured cannabidiol and tetrahydrocannbinol metabolites in urine to differentiate marijuana use from consumption of commercial cannabidiol products, Clinical Toxicology 2021, 59(6)
[2] U. Meier und Kollegen, Cannabinoid Concentrations in blood and urine after smoking cannabidiol joints, Forensic Science International 291 (2018), 62-67
[3] T. R. Spindle et al., Urinary Pharmacokinetic Profile of Cannabinoids Following Administration of Vaporized and Oral Cannabidiol and Vaporized CBD-Dominant Cannabis, Journal of Analytical Toxicology 2019; 1-17
[4] D. J. Sholler et al., Urinary Pharmacokinetic Profile of Cannabidiol (CBD), ∆9-tetrahydrocannabinol (THC) and Their Metabolites following Oral and Vaporized CBD and Vaporized CBD-Dominant Cannabis Administration, Journal of Analytical Toxicology 2021, 00: 1-10
[5] S. Vikingsson et al., Prevalence of Cannabidiol, ∆9- and ∆8-Tetrahydrocannabinol and Metabolites in Workplace Drug Testing Urine Specimens, Journal of Analytical Toxicology, Volume 46, Issue 8, October 2022, Pages 866–874, https://doi.org/10.1093/jat/bkac013