Actually saliva drug screens are mainly for 4-6 hours prior to use,, I smoke a bowl and the very next day I got one of these tests..And I passed it!! Check out this site,, www.asltesting.com it is someone who actually sells the tests and tests it and it will give you some info
Yes it goes back 6-months
Saliva is usually used for DNA testing.
Actually saliva drug test is what marijuana smokers want... You could stay sober for about a week and be clean.. Saliva tests are mainly for crack cocaine addicts.. It stays in their mouth longer then in the urine ...