Why take a chance? Subbing is sooo easy and low stress.
I just did it.
Buy the quick fix, microwave it for about ten seconds. The bottle has a temp strip across the bottom. The green number is the temperature.
Slip it in your underwear and walk into the testing facility.
Pour it into the cup, pee in the toilet and walk out the door knowing the new job is secure.

Do not sweat this.
No worries, for real, and I am a nervous type about these things.