parasite testing is known to be unreliable - best testing is:
1/ ParaWellness Labs (cost $300) they send a test kit out -wait time is about 3 weeks.
2/ Dr. Kevin Cahill in NYC (cost about $500 plus airfare)
3/ Metametrix GI Effects panel #2105 (cost less than $300) has advanced testing method but many receive a PPTU diagnosis which means identification is unknown. Better than nothing.
Each of these have advantages and disadvantages - may have to do more than one test.