The temp has to be between 90-100 for most tests. Some tests use 92-98. Of course I know they test the temp when you give it to them but it is not that hard. The best way to sub successfully is to find a good 2 ounce bottle and practice hiding it and keeping it the right temp. If you put a sample against your body that is already at body temp your body heat will keep it between 90-100. If it is at room temp it will take your body heat about 30 minutes to one hour to bring it up to temp. It sounds hard to do but with practice you can do it.