SEP 15, 2020 3:45 PM PDT

Cannabis Blood Tests Unreliable for Testing Intoxication

WRITTEN BY: Annie Lennon

Researchers from the University of British Columbia have found that tetrahydrocannabinol (THC), the psychoactive compound in cannabis, can be detected in the body for up to a month after consumption. As such, they say that cannabis blood tests are not reliable in saying whether someone has just used the substance or is under its influence.

For the study, the researchers conducted a systematic review of existing literature on residual blood THC concentrations in frequent cannabis users after a period of abstinence. Of 1612 articles initially identified for review, they ended up including six studies in their analysis- the only studies that met their inclusion criteria. 

All in all, the researchers found that THC concentrations of 2ng/ml and above could linger for extended periods of time in the bloodstream, and far beyond time periods in which a person could be under its influence. 

In particular, the researchers noted that THC levels among some participants remained above 2ng/ml several days after abstinence- with some testing positive for up to 30 days. Some participants even displayed a ‘double bump’ pattern in which their THC levels rose towards the end of the week after declining. Others maintained THC levels above 5ng/ml a day after abstinence. 

As such, the researchers say that measuring THC levels in the blood is not a fair assessment of recent exposure to cannabis and can not reliably indicate whether someone has recently been using the substance and is still feeling its effects. 

The researchers thus say that law enforcers should refrain from using THC blood to uphold road safety laws, which often have a zero-tolerance to cannabis use. To properly uphold these laws without incriminating innocent individuals, they recommend more research to be conducted into more reliable ways to assess whether people are under the influence of cannabis at a given moment. 

 

Sources: High TimesScience Direct

About the Author
  • Science writer with keen interests in technology and behavioral biology. Her current focus is on the interplay between these fields to create meaningful interactions, applications and environments.
You May Also Like
MAY 12, 2020
Cannabis Sciences
Cannabis Use Not Linked to Low IQ
MAY 12, 2020
Cannabis Use Not Linked to Low IQ
While 12% of adults in the US claim to have smoked cannabis, the same figure stands at 22% for those aged between 18 and ...
JUN 02, 2020
Cannabis Sciences
Ancient Israelites Used Cannabis to Experience God
JUN 02, 2020
Ancient Israelites Used Cannabis to Experience God
Researchers have found evidence that ancient worshipers in Israel may have used cannabis to experience God over 2800 yea ...
JUN 23, 2020
Health & Medicine
New Evidence Medical Cannabis Can Lead to Decreased Opioid Use in Chronic Pain
JUN 23, 2020
New Evidence Medical Cannabis Can Lead to Decreased Opioid Use in Chronic Pain
For people with long term ongoing pain, medical cannabis is a valid option that could pave the way to reduced use of opi ...
JUL 08, 2020
Health & Medicine
The Myths About CBD and Coronavirus
JUL 08, 2020
The Myths About CBD and Coronavirus
Research collected over the last 20 years suggests that cannabidiol – the primary cannabinoid in CBD oil – h ...
JUL 13, 2020
Cannabis Sciences
Cannabis Briefly Alleviates PTSD Symptoms
JUL 13, 2020
Cannabis Briefly Alleviates PTSD Symptoms
Therapy is the primary recommended treatment for individuals with post-traumatic stress disorder (PTSD), but a new study ...
AUG 14, 2020
Health & Medicine
Does Legalization of Cannabis Mean Users Actually Use Legal Sources?
AUG 14, 2020
Does Legalization of Cannabis Mean Users Actually Use Legal Sources?
Recent research from states that have legalized recreational cannabis, looked at whether users find the drug  is mo ...
Loading Comments...