THC in blood: How long can THC and his metabolites be detected in blood?


THC in bloodTHC in blood: How long can THC and his s be detected in blood?

With usual tests 0.5 nanograms per milliliter (ng/ml) of THC and 0.5 ng/ml of its THC-COOH can be detected in blood plasma. The time until falling short of this detection limit after consumption varies considerably, even if the same amount of THC was ingested.
After a low dose cigarette (about 16 mg THC) the detection limit of 0.5 ng/ml THC in plasma was reached after 7.2 hours on average (range: 3-12 hours) and following a high dose cigarette (about 34 mg THC) a plasma concentration of 0.5 ng/ml THC was reached within 12.5 hours (range: 6-27 hours). The THC-COOH was detectable for a considerably longer time, for 3,5 days (range: 2-7 days) after the low dose and for 6,3 days (range 3-7 days) after the high dose cigarette.
The elimination half life for from plasma is longer than the elimination half life of the THC itsself. With regular use THC-COOH may be detectable in the plasma for several weeks.

Modified according to: and pharmacodynamics of . Clin Pharmacokin 2002, in press.

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