Our online patient portal, MyMercy, enables patients to conveniently access portions of their medical records and view test results.MyMercy is free to use, simple to sign-up for and is completely secure. Only you and your care team will have access to your private health information. MyMercy Patient Portal. On May 8, 2019, MercyOne Siouxland Medical Center updated the security of MyMercy where ....