about temperature

i was wondering about with the dipstick tests, they have little thermometer gauges on the bottom, but does it have to be the right temperature for the test to work? like, if i use cold piss that is clean of thc, will the test still say negative or will it say retest.
because my paretns dont ever look at the thermometer.

also, i was going to put the bottle of cold piss into a sink of hot water, to heat up the piss. like with the bottle closed. would that work do you think?

help is very appreciated