I have used the firstcheck brand that was a 2 panel THC and COC test. they're one time only. the THC cutoff is 50 ng/ml which is the prescreen level for most lab tests. so theoretically if you pass that you'll be good to go since there won't be any reason for them to use the more advanced tests that have 15ng/ml as a standard.

Help me:
http://boards.cannabis.com/drug-test...a-ok-am-i.html