I stand by my statement! I will believe my good friends at NORML before some bongmaker on Erowid.

"BLOOD TESTS: In some situations, including accidents and roadside sobriety checks, blood tests may be used. Blood tests are a much better gauge of current impairment than urine tests because they detect the actual presence of THC in the system; however, they can be sensitive to other metabolites as well. Blood tests generally register positive for just a few hours after smoking, though heavy chronic smokers may be positive for a couple of days. Less sensitive are saliva tests, which register positive for about 2-4 hours after smoking. If you have used marijuana in the last few days but are not currently under the influence, you should insist on a blood (or saliva) test instead of a urine test if at all possible, since you are more likely to turn up clean. On the other hand, if you have smoked recently, you may do better to take a urine test, since this will at least leave open the question as to whether you were under the influence. Also, urine doesn't turn positive until several minutes after smoking. http://www.norml.org/index.cfm?Group_ID=4934#blood

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IamN2pot Reviewed by IamN2pot on . butterfly_UK Please help.... I have to undergo a pre-employment medical, which includes drug screening I have already handed in my notice at my current employment and now find myself in this terrible predicament I know they are going to take a blood testâ?¦so any factual tips and advice would be very helpful I last smoked weed/cannabis on the 6 June 2004 and the drugs test is on the 8th July 2004 oh i forget to say i have smoked weed/cannabis for years - at least 2 spliffs everyday Rating: 5