Alright, I joined to add my two cents and confirm what the OP has said. Had a LabCorp test a couple of weeks ago in California. Used Quickfix Plus 5.7-1 *CANADIAN VERSION* with uric acid (it will say Canadian batch on the instructions, says "made in USA" on the outside). Always double-check the urineluck website to make sure your batch hasn't been recalled. Anyway, microwaved it for about 10 seconds then rubber-banded the heat pack to the bottle. Used one of those ACE bandages from Walmart to keep the whole thing attached to my leg. Wore boxer briefs and an extra pair of boxers over it all, just in case. It was about two hours before I finally got called in from the waiting room. The heat pack stayed warm the entire time and would have stayed much longer (they say it will last up to five hours). Next time, however, I might not even use the heat pack. I've heard that many people have great success just keeping it attached to their body, as long as it's close enough and insulated enough (with clothing or otherwise) to keep it body temperature, and as long as you preheat it in the microwave. Also, as long as you remain relatively calm and dress semi-professionally when you go in for your test, they aren't likely to suspect anything.

Anyway, here are my tips and problems I ran into.

TIPS:
- Keep the heat pack on the opposite side of the temperature strip when/if you rubber band it to the bottle (you don't want direct contact with the heat pack to interfere with your reading).
- Don't use sticky tape to attach the urine kit to yourself -- I was in a really quiet restroom with a lady standing a few feet outside. Sticky tape would have been too noisy (use ACE bandage).
- Be careful if you're going to use the spray-nozzle attachment for the Quick Fix bottle. It can sometimes makes a 'ketchup-bottle sucking' noise when you let it "breathe in" after you squeeze it.
- Don't over-wrap the bottle or make it too hard to access. You're dealing with a limited amount of time. She only gave me two minutes before telling me to hurry up.


PROBLEM:

- Temperature was too high when I checked the strip! Fortunately, this is a lot easier to deal with than it being too low. When I first checked the temperature strip, there was no reading but it felt too warm to be under 90. I knew the head pad was working, plus everything was attached to my body so it had to be more than 100 deg rather than less than 90. I simply swished the entire bottle around in the cool toilet water for about 30 secs to try and cool it down (if they use dye in the water, just make sure you don't get it on your hands and wipe any excess of on an interior layer of your clothing). After wiping the wetness off of the temp strip, I was within the range (about 98 degs). I've since read it might have been easier to simply pour the "urine" into the sample cup first and just swish it around in air to cool it off but I wanted a reading before I poured it since I've heard the heat packs can sometimes overheat to 120+ degrees. I suppose it depends on whether or not you're being rushed, so just pour some out and swish it around in the cup for a few seconds if you have to. Don't make them wait too long or you may have to re-test.

Anyway, that was pretty much it. The "fill line" for my sample cup only required 1/4th of the Quick Fix bottle. It's not as hard as it may sound but I know I appreciated every bit of info I was able to find. Just make sure you have an "exit plan". You can either put the used bottle into one of your pockets on the way out or into your "tighty whities" but just make sure you have somewhere to put it (and that its closed).

Peace.

EDIT: (P.S. I passed.)