I think I posted this in the past but it bears repeating. I had a stool test for parasites done by an integrative medicine physician who used a company called Metametrix. The test has only been commercially available since 2007. It diagnosed ascaris, a worm which lives in the small intestine. Killed it with four pills. I'd had many stool tests in the past and nothing came up. Don't leave this stone unturned....I'm glad I did it.