So I had my day at MEPS yesterday, to enter the Marine Corps. Before going to MEPS, I had been clean from weed for exactly four weeks. Before that, I smoked mostly daily from maybe November 2013 to this April, but I've always been an extreme lightweight (a gram or two of top-shelf would last me a week). I'm 5"10 and 145 pounds, always had a pretty fast metabolism. 12 days before my MEPS date, I took an AtHome drug test with my first void of the day, and passed with a nice clear line. The day before MEPS, I took another AtHome test (again, first void of the day) and had a similarly clear line. Then I went to my recruiting office, where I was tested once again (this time with an iCup test), and passed, although the line was extremely faint. My recruiter noticed this too, but didn't seem too concerned. At MEPS, I drank about 30oz of water before my drug test, cleared my bladder several times that day, and caught the urine mid-stream in the cup. The urine was a very pale yellow color. The nurse put some sort of swab in the urine, then sealed it with red tamper-proof tape and boxed it up. The swab kind of freaked me out, because everything I had read online says the samples go through an AU-800 EMIT immunoassay, then a GC/MS lab test for those that come up positive. Nobody said anything about any testing being done on the spot— what was that about? I was really confident before I went in, but now that it's out of my hand, my mind keeps coming back to the stories I've heard of people passing at home immunoassays and then receiving a letter saying they failed at MEPS. Apparently these letters can take a week or two to arrive, and I'm going half-mad with anxiety. Can anyone with some familiarity with drug tests (especially regarding MEPS and their protocol) chime in here? What was up with the swab test they did on the spot? How likely is it that I'd fail my test after the negative at-home tests? Thank you in advance.