As a native of Boulder, Colorado,
this is my personal nightmare. A new study has found that chemicals indicative
of marijuana consumption may be found in hair samples even if you've never ingested marijuana. A new German study
found that both ∆9-tetrahydrocannabinol (THC), its metabolite 11-nor-9-carboxy-Δ9-tetrahydrocannabinol
(THC-COOH) and another THC precursor Δ9-tetrahydrocannabinolic acid A (THCA-A)
make their way to the hair shaft mainly through transfer of sebum onto the hair,
but that touching hair after touching marijuana (not smoking it!) may also lead
to a positive test result.
Interestingly, greater
concentrations of TCH were found in beard, pubic and axillary hair regions,
(apocrine glands?) although alarmingly, THC-COOH can be detected in the hair of
two year old children at a concentration that would be expected of an
individual regularly consuming THC. It has been hypothesized that close body
contact or even sharing a pillow with a THC consumer can transfer detectable
amounts of THC and THC-COOH to the non-user.
This brings up another point:
aside from possibly implicating innocent people, there ought to be a way to
distinguish regular marijuana users from those that do not “ingest herb”, “blaze”
or my personal favorite “take the elevator” (credit to yahoo answers username OoohAPieceofCandy.)
If measureable quantities of THC can be transferred that easily, this also has
large implications for child custody and other drug tests, and better long term
testing methods ought to be developed.
Moosmann, B. et al.Finding cannabinoids in hair does not prove cannabis consumption. Sci. Rep. 5, 14906; doi: 10.1038/srep14906 (2015).
http://www.nature.com/articles/srep14906
This is super interesting as Denver might be going to hair testing for motorists who seem to be under the influence of marijuana. They are doing a blood test right now but, most experts believe the limit they set is fictitious and can't show that a person was under the influence at that very moment. I know the hair test can show when a person ingested THC up to a few years out. But, this brings new light into that being a useful strategy too. If I can potentially be driving someones car, that person smokes on a regular basis in their car, and my hair touched their headrest that is covered in marijuana smoke or marijuana particles I could potential get a DUI for it if they start doing hair tests even though I never smoke. I think this whole marijuana testing strategy needs to become more refined before they can just start charging people with DUIs or even worse taking there children away. There is no definitive test to show that you smoked or ingested marijuana at a certain time and one needs to be developed.
ReplyDeleteI actually just had a friend who went through this! She tested positive for THC after a routine drug/hair test at her work and she had to go back and get a blood test to confirm that the hair test was inaccurate. Hair testing has been likened to rings on a tree in that you can essentially map out a person's personal health history, including drug usage over the past few years. I wonder if the technology that does hair testing can distinguish the timing of the usage or is someone screwed over for some marijuana they consumed last year? I also found it interesting that the THC makes its way into the sebum which is secreted by the sebaceous glands. How does this work in an adolescent sine most sebaceous glands aren't active until puberty?
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