Storm Crow
06-12-2007, 02:02 AM
Science: Detection time of regular THC use in urine shorter than
often assumed
According to a review in the current issue of the journal Drug
Court Review "it is uncommon for occasional marijuana smokers
to test positive for cannabinoids in urine for longer than seven
days using standard cutoff concentrations. Following smoking
cessation, chronic smokers would not be expected to remain
positive for longer than 21 days, even when using the 20 ng/mL
cannabinoid cutoff." By using a cut-off of 50 ng/ml in drug
screening assays the detection window would typically be not
longer than ten days for regular users and between 3-4 days for
occasional users.
The author, Dr. Paul Cary of the University of Missouri, noted
that it is usually assumed by scientists, the legal system and users
of cannabis that the use of cannabis is detectable in the urine by
drug screenings 30 days or longer after last consumption.
However, he points out that many studies that found a long
detection time had major methodical weaknesses. The most
serious of these limiting factors would be "the inability to assure
marijuana abstinence of the subjects during the studies."
Despite these limitations of the available studies his analysis
revealed that very long cannabinoid detection times (30 days or
more) are rare. The average detection window for the THC
metabolite THC-COOH in urine of regular cannabis users at a
cut-off concentration of 20 ng/ml in the studies reviewed by Dr.
Cary was 14 days. In many of the studies "only one single
subject was the source of the maximum cannabinoid detection
time." He concluded that "these rare occurrences have had a
disproportional influence" on the perception on the length
cannabis use can be detected in urine after last consumption.
The full text is available for free at:
http://www.ndci.org/NDCIR%20VI.pdf
(Source: Cary PL. The marijuana detection window: determining
the length of time cannabinoids will remain detectable in urine
following smoking: a critical review of relevant research and
cannabinoid detection guidance for drug courts. Drug Court Rev
2005;5(1):23-58.)
-Granny:hippy:
often assumed
According to a review in the current issue of the journal Drug
Court Review "it is uncommon for occasional marijuana smokers
to test positive for cannabinoids in urine for longer than seven
days using standard cutoff concentrations. Following smoking
cessation, chronic smokers would not be expected to remain
positive for longer than 21 days, even when using the 20 ng/mL
cannabinoid cutoff." By using a cut-off of 50 ng/ml in drug
screening assays the detection window would typically be not
longer than ten days for regular users and between 3-4 days for
occasional users.
The author, Dr. Paul Cary of the University of Missouri, noted
that it is usually assumed by scientists, the legal system and users
of cannabis that the use of cannabis is detectable in the urine by
drug screenings 30 days or longer after last consumption.
However, he points out that many studies that found a long
detection time had major methodical weaknesses. The most
serious of these limiting factors would be "the inability to assure
marijuana abstinence of the subjects during the studies."
Despite these limitations of the available studies his analysis
revealed that very long cannabinoid detection times (30 days or
more) are rare. The average detection window for the THC
metabolite THC-COOH in urine of regular cannabis users at a
cut-off concentration of 20 ng/ml in the studies reviewed by Dr.
Cary was 14 days. In many of the studies "only one single
subject was the source of the maximum cannabinoid detection
time." He concluded that "these rare occurrences have had a
disproportional influence" on the perception on the length
cannabis use can be detected in urine after last consumption.
The full text is available for free at:
http://www.ndci.org/NDCIR%20VI.pdf
(Source: Cary PL. The marijuana detection window: determining
the length of time cannabinoids will remain detectable in urine
following smoking: a critical review of relevant research and
cannabinoid detection guidance for drug courts. Drug Court Rev
2005;5(1):23-58.)
-Granny:hippy: