I really take those tests with a grain of salt, I had bunches of those tests done (EAV etc) - to me they might get in you in a general area but I would not rely on these implicitly.
Start with a worm killer and see where you get, you should see remnants of the dead parasite (assuming worms) in the toilet. If you don't get results then consider testing with Metametrix, ParaWellness labs etc.