I have the same concern "Can anyone definitively say if the first check home test kit is truly accurate about the presence of faint lines vs. what a true lab test may identify?" These posts above were from 2008 to 2009. My concern is for now 2011. Has anything changed or upgraded at the labs to detect THC? Are test in labs in 2011 now more accurate or more sensitive than 2008 and 2009? My Lab test was at 3pm yesterday. I smoked 4-5 blunts within 17 days before my lab test. But the very last time was 7 days before the lab test yesterday. I drank massive water and cranberry juice 2 days before my Lab Test. On the day of lab test, I flushed starting 3 hours before the Lab Test (at 12pm) with Ultimate Blend 24 (which can be found at most smokeshops). I did the First Check Home kit test at 2:35pm and showed negative with very very faint lines. Since it was faint lines and the box stated that faint lines falls under "negative", I went ahead and Took the Lab Test at Quest Diagnostic at around 3:05pm. I then rushed home to do another Home Kit Test which then appeared completely negative at 3:45pm. So if it was faintly negative half hour before The Lab and then completely negative with solid lines 40 minutes later after the Lab test, is that safe to say that the Lab will detect a "Negative"? I haven't been called yet from the job even though its only been 29 hrs and I am worried sick. I do not want to lose out on the job opportunity. Please help me and let me know.