Plain-language guides to the public Medicare enrollment and provider data this tool checks — with a live, evidence-backed lookup behind every one. See also data sources & methodology.
What Medicare reassignment of benefits means, how the public CMS reassignment data links individual and group enrollments, and how to check a provider's reassignment relationships by NPI.
An NPI identifies a provider; PECOS is Medicare's enrollment system. What each one is, why a valid NPI does not mean Medicare enrollment, and how to check both signals free.
How to check a provider's public PECOS enrollment signal by NPI without a login, what the public CMS file does and does not show, and why enrollment is not the same as participation.
What a Medicare opt-out affidavit means, what the public CMS opt-out file shows — effective and end dates, order-and-refer status — and how to check any NPI against it free.
How to find a Medicare revalidation due date by NPI, what an adjusted due date is, what a not-posted date means, and why missing revalidation risks deactivation.
What the CMS Order & Referring file means, the five program contexts it covers — Part B, DME, Home Health, PMD, Hospice — and how to check a practitioner's flags by NPI, free.
How to run an OIG exclusion check by NPI, what an LEIE match is (a review signal, not a verdict), where SAM.gov and state Medicaid lists fit, and why screening recurs.