Well, your best bet, if at all possible, is synthetic urine. The Only difference between good fake urine and real urine is dna, and they are doing a drug test, not a dna test! You can warm it up pretty fast. Synthetic urine has a shelf life of a year. Quick Fix is real good.
Real urine needs to be used in 8 hours, because it starts to grow bacteria but it can be frozen for a year in something air tight.:thumbsup:
Hope this helped!