There are diagnostic tests available for candida, including stool analysis and blood antibody tests. Great Smokies Diagnostic Laboratories performs these tests, as well as other functional medicine tests, including parasites. There website is:
www:gsdl.com
Also keep in mind that there are a tremendous amount of Antibiotics and hormones in our food supply...routinely used by meat and poultry suppliers...so we consume them regularly even if we've never had a course of pharmaceutical Antibiotics or hormones.