Hair analysis no clear evidence of cannabis use

So far, it was considered certain that at least the detection of specific degradation products of the main cannabis active ingredient THC in the hair a consumption prove beyond any doubt. Researchers from Freiburg could now show that this conclusion is not allowed.

Storage of THC does not take place via the bloodstream when taking THC. Also, a breakdown product of THC, which has been used in cases of doubt so far for the clear evidence of consumption, can be transferred via sweat and sebum of a consumer to other persons.

"The new findings are particularly important in the analysis of child hair samples in the context of custody issues, as a cannabinoid transmission in close contact with the body is particularly likely and can lead to completely wrong conclusions," say the study authors. In countries where drug screening is carried out on workers or applicants, the result of a misinterpretation of the results of a hair analysis could lead to job losses or exclusion from the application process, according to the experts. (Pm)