What phone number do I use to talk to someone about whether certain procedure codes are covered by Medicare or not?

Call the Medicare number on the Medicare explanation of benefits notices.

May I ask why you're concerned and are calling? Medicare coding is complex and can be a labyrinthine process. I just went through this to ensure that all aspects of PT were covered and learned that some modalities provided aren't billed separated but are "bundled" with the therapy.

Although coding mistakes are made, usually the people doing the coding know how the system works.

I found this website helpful... scroll down to the bottom of the page and click on what you need to find the telephone numbers.

https://www.medicare.gov/coverage/is-your-test-item-or-service-covered.html