They are not acurate and testing for every species of parasite doesn't even exist. Everyone has parasites, everyone! If you are living, something is living off of you unless you kick them out. Do some good cleansing. Case in point, Tapeworm stages can be throughout the entire body and just because they don't come out in the stool doesn't mean they aren't there. Case in point, lung flukes and blood flukes might not be found in the stool but it doesn't mean they aren't there.