Just posting some notes on my experience as reading those of others helped me learn a lot and eased my stress... I got a good job offer, contingent upon passing a pre-employment drug screen. I am a 230 lb. male, 5'8", slow metabolism, low activity level. Up until March 3 (17 days ago as of this posting) I was a pretty heavy smoker of high quality herb - about a quarter a week, sometimes less. I stopped when I found out about the drug screen, but given all that I have read I was not comfortable doing the dilution method. I bought some home tests at Rite Aid and of course tested positive. I did read the dilution thread and did a practice run about 10 days ago, and a home test came out negative following N2's advice. But I was still worried that if my specimen was tested using GC/MS which has a lower threshold that it might still come out positive. I did another home test using my first void of the day this morning, and it came out positive (there may have been a very faint line on the results stick, but I think I was seeing the whitish wax line that you can see if you hold it at an angle and not a true negative indicator). So I decided to go the substitution route. I bought a bottle of QuickFix 4 at a local head shop. The proprietor swore by it and said he sold more of that than anything else there. I received the Quest Diagnostics Forensic Drug Testing Custody and Control Form yesterday and decided to go in for my test today. On the form it indicated that the test to be performed was "6633N SAP 10-50 GC/MS". I've read elsewhere in this forum that this is a ten panel test at the 50 ng cutoff and that the GC/MS test would only be done if my specimen failed the initial screen. Call me paranoid, but I was still worried that I might not pass the GC/MS test, so that is why I decided to substitute. A couple other things I will point out for those that have not seen one of these forms. There is a "Reason for test" section on the form with several choices - Pre-employment, Random, Reasonable suspicion/cause, Post-accident, Promotion, Return to duty, Follow-up, Other. Nothing was selected on my form, and when I went in today the specimen collector asked me if it was for Pre-employment. I said yeas and she checked that box. There is also a section that says "Read specimen tempurature within 4 minutes. Is temperature between 90 degrees and 100 degrees F?" and then check boxes for "Yes" and "No, Enter Remark". After that there is a box labelled "Specimen Collection" with check boxes for "Split", "Single", and "None Provided (Enter Remark)". After that there is a box labelled "Observed (Enter Remark)". This was unchecked, and I was not observed during the test. Question for the mods or anyone else who might know - under what circumstances do they collect split or single? Is there any significance to that? In my case they marked single and just had me initial a single tube of collected specimen. Just wondering what, is anything, that signifies... So, this morning I started the Dilution routine outlined by N2 just as a backup. I opened the warming pad that comes with the QF and let it warm up about an hour before I was going to leave my house. Once it was warm I nuked the bottle of QF (cap off) for about 8 seconds to bring it up to 98 degrees. Then I capped it, affixed the warming pad with rubber bands on the non-tempstrip side of the bottle, and then stuffed it between my scrotum and anus underneath two pairs of snug boxerbriefs (I tried it between the two pair of boxer briefs but was not satisfied it would stay in place). When my clear voids starting turning yellow (about 90 minutes after taking 10 crushed vitamin B2 tablets in gatorade - yuck!), I left for the test center about 10 minutes away. Of course I took the wrong exit and turned a 10 minute trip into a 30 minute one. On the way I had to stop and pee at a fast food restaurant, and when I checked the QF bottle it was a nice 98 degrees. Yay! I arrived at the test center and signed in. After about a 15 minute wait while I distractedly read a book (I don't even remember what I read), they called me back. It was a cramped office with the specimen collector sitting at her desk right outside the bathroom. She told me to empty my pockets into a lockbox (though she did not check toi verify they were empty) and leave my jacket on the chair. She told me to wash my hands at a sink that was right by the desk and not to use any soap. Then she gave me a bog cup. At first she said to fill it, and then she changed her mind (wtf?) and marked it with a pen and said "Just fill it up to here". So I went in to the bathroom and locked the door behind me. It was just a toilet that had blue water and nothing else. I pulled out my QF and poured it in slowly to minimize the glug-glug sound (though I don't think she would have heard me because the radio was on and she was yakking with her officemate). The QF filled the cup to about twice the line she said was required. It was about 94 degrees in the specimen cup. Then I peed in the toilet, stopping halfway as if I were filling the cup and then resuming. I stuffed the QF back in my shorts and took the cup to her. She poured about half of it into a tube which she sealed and asked me to sign. Before she did that though, I asked if I could wash my hands again. She told me to wait until she seaed the tube. It occurs to me that if you could get away with turning your back on the collector to wash your hands before the tube was sealed that you would have grounds for appeal should the test come back positive or dillute or whatnot. But no dice this time. She checked the box indicating the temperature was in acceptable range. On the Remarks section she wrote (I think - hard to read) "Retraced date seal A". Seems pretty inocuous, but does that mean anything I should be concerned about? So she had me initial the tube and then sign the form. For a second or two I totally blanked on the date - and not just the day but the month too! I think I was in some kind of fugue state after all the stress and worry, even though I was outwardly calm. Anyway, everything was cool. I collected my stuff and gave her a cheerful goodbye and was on my way. I'm still a bit paranoid and will be until I find out the results (or start work on March 31 which would be an implicit negative result, wouldn't it?) I can't help but worry that they will somehow be able to find out the QF is not real pee and will nail me on it. I know I am just being paranoid...but that's how you feel after duping a drug test. Long post, I know, but I just wanted to share my experience since reading about others' experiences here really helped me a lot. I hope this in turn helps others. Thanks for everything.