I got a series of swabs done for mine - they gave me 6 kits to take samples myself and I tested once a month and sent the samples off in the post to the gynaecologist. I tested positive on 50% of the samples. I periodically test positive at other times when I'm tested.
You could also get a candida antibody test (a blood test to check for candida antibodies). If you have antibodies this is supposed to mean to are allergic to candida and even tiny amounts can cause problems, although the test is a fairly new thing and a bit controversial (not sure how accurate it is) so you might not be able to get it at your hospital but you could buy one. Private companies that do allergy testing sometimes do these.