If this job is really important to you you can buy a home test kit and test your donor.

You should also practice your subbing run by getting the container you are going to use fill it with about 2 ounces of water and securing and checking to see if you can keep it at body temp. If the sample starts off at 90-100 degrees your body heat will keep it around 96 degrees unless there is too much cloth or wrap insulating the body heat from the container.