Posted By Dee Jeffery, This might help: How long drugs are detectable in the system depends on a number of factors: The drug taken How much and how often taken Body weight Individual metabolism Sensitivity of testing used Body fluid/tissue used (blood, plasma, urine, saliva, sweat, hair) Other substances taken (e.g. dilution of urine sample, masking agents or adulterants) A single hit of cannabis may disappear in a few days, whereas heavy or chronic use can be detected in urine up to a month after stopping. Amphetamine is detectable for up to a week. A low level of cannabinoids in urine can readily be produced from passive exposure to cannabis smoke, from being in a room, car, bar, concert etc with others who are using. If a responsible test is used, there should be a cut-off level below which a negative result would result, to avoid 'false' positives from passive exposure. The more sensitive the test, the greater the number of false positives, and the longer period for detecting drugs in urine after the last use. One way to minimise the risk of a positive result is to avoid giving a sample from the first pee of the day, and to maximise the volume of urine produced e.g. by drinking plenty of water or coffee (caffeine is a diuretic) before the test. Dee

Posted By David Daniels Jeffrey It also depends on the sampling methodology. Hair sampling can go back months urine sampling can certainly go back a number of weeks. There is a very good testing kit that can be used for drugs and alcohol that I can give you some info for if required

Posted By Raymond Rapp I am no expert, but I suspect there would not be a method to inconclusivley determine when someone imbibed cannabis. It's akin to asking how much it would take to effect cognitive reaction. There is no answeras each individual will be affected diffrently. Still, if you wish to puruse it further try Medscreen or Medical Express, who are approved D&A testing companies. Ray

Posted By John Doe I'm sure I've read something that said cannabis can remain in the user's hair for around 13 weeks. Anyone else heard this? I'll try and find it but if you know this to be absolute rubbish, please save me the time.