Whether or not you need a referral depends on what kind of health insurance you have. I self-referred to Mayo for a second opinion while I was still working and had employer-sponsored insurance. Mayo took that insurance, fortunately. Now I’m on Medicare, with a plan G supplement. Mayo takes Medicare with a traditional supplement, but they do NOT take Medicare Advantage. Call or email all the places you’re thinking of going and see if you can speak to a patient advocate who can help you navigate the ins and outs of insurance.