One of the smallest jurisdictions for a Medicare MAC is A/B MAC J15, which is Ohio and Kentucky. It currently belows to the CGS MAC, which shares ownership links with Palmetto MAC.
The MAC was put out to bid last October, 2021, and I ran across a 172 page Statement of Work. If you'd like a current MAC SOW as a reference, here's a link to it:
TOPIC: MACS AND FOIA
For example, page 157-158 talks about running a FOIA office at the MAC, something that has quite variable diligence and quality at different MACs. (See my blog, Lamest FOIA Response Ever, here.)
J15 is part of the MOLDX policy system, but there is nothing about MOLDX or molecular testing in the SOW for J15. That is executed via a separate MAC-to-MAC agreement. However, the last time I checked, MOLDX was included as part of the statement of work baked into the MAC for JM, which is Palmetto.
TOPIC: DIALOG WITH MEDICARE ADVANTAGE
Page 169 talks about how MACs are obligated, as part of their SOW, to share information with Medicare Advantage plans and "maintain an ongoing dialogue with these entities" to provide the MA plan with "information...needed to administer their plans." MA plans are supposed to match FFS Medicare in terms of coverage.