My daughter used the antibody test result from the lab her doctor sent her to. She lives down there so it was a local one. She had no problems returning to the island a couple of times.

Regarding PCR tests - on the second page of the portal instructions, there is a link to the approved labs. In the advanced search you can search by geographic location.
"3. I understand that the laboratory I select to perform my COVID-19 test, including those that offer in-home, mail-in services, should be certified under the Clinical Laboratory Improvement Amendment (CLIA). https://www.cdc.gov/clia/LabSearch.html."