I've done them for parasite testing, cancer tests, and bacteria testing, but for surgery they weren't required. I did do a breath test for H. Pylori though, which could be what they are looking for.
It weirds me out to do the stool tests but I'll tell you how I do it. I fill out the bottle labels. Open a trash bag and put it in the sink with the sides up the edges of the sink. Once I've used the bathroom in the plastic thing I nestle it inside the trash bag. Do the gloves and take the sample thing. Toss everything else into the bag, shuck the gloves, pull the bag sides up and viola, everything is disposed of!! I might have had to do these a lot for a GI condition I used to have that involved GI bleeding.... There is always a method to my madness.