oral swb screening

so im new to this site, as well as the whole blogging thing. hopefully someone will tell me where to find the right information, but for now lets start with this. I have an oral swab drug screening coming up very soon, and ive got to say every bit of information ive gathered is has minor alterations, and therefore ive not been able to find a truly reliable source. My question is this: how long in marijuana detectable through saliva? i tend to smoke about once a day, sometimes as much as 4-6. But for the most part I smoke once a day, of which i only smoke a bowl at the time. Im worried that I may not pass this screen because it is for a great job, but it has been 3 days since ive smoked bud. im hoping someone has some sort of answer, it would be greatly appreciated.