Nationwide as it is online similar to the eMed/Navica testing. Several folks have posted on John H's page and in other groups that I am in that they have done this without issue.
There are services out there such as OnPoint and others where you pay a nominal fee ($15 to $20) for video/telehealth appointment and use whatever test you already have.
My wife has an SCS implanted in her back and on all of our cruises she just shows her card and bypasses the magnatron and goes through a physical pat down or wanding. Never had an issue.