@shoileygal
Just want to clarify, the Mayo Clinic / United Healthcare relationship your referring to is just for Mayo Clinic Rochester and Mayo Clinic Health System sites in the Midwest.

See announcement:
https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-unitedhealthcare-agree-to-multi-year-commercial-and-medicare-advantage-relationship/
As Colleen mentioned earlier, is best to contact a coordinator at Mayo Clinic Billing & Insurance https://www.mayoclinic.org/billing-insurance/contact-us to see if your insurance is accepted at that Mayo location.