[jcope82]

...take blood samples to test for alcohol, do they test for drugs as well? and does blood testing show the prescence of metabolites or just the psychoactive substance? what about marijuana, how long does it show up in blood test after its use? I know a lot of people say it stays in blood for a long time but most articles on the internet say it can be testable for only a few hours and maybe up to twenty four in chronic users. please only post if you know what you are talking about.

[Kevin]

They will test for several controlled substances, any of which would constitute a DUI.