OK....urine is best kept in fridge if not needed right away. It will keep in the fridge for approx 5 days. You will have a nice 8 hour window to play with before the urine starts to go bad...not saying it will be bad at this point. Keep in fridge tonight. In the morning before going into work just place 2oz bottle between whitie tighties with warmer IF you don't think you will be tested as soon as you walk into the door. Otherwise, it'll give it time to warm up and last longer during the day.