One thing you could do is go to an allergist and ask them to test to see if you are allergic to candida. If you are allergic to candida, it means that your body isn’t fighting it. You then could get prescribed candida hypersensitization shots (costs about $750/6months US) which then increase your immunity to yeast. It might be the closest thing to a diagnosis out there other than the candia5 test.
Another thing you could do is go to a GI doctor or allergist and get some of these test done (but at european labs):
The problem with these tests is the cost and you might need a combination of 2-3 of them for positive diagnosis. Additionally they may not be conclusive.