Hospitals and CAHs are required to provide a MOON to Medicare beneficiaries (including Medicare Advantage health plan enrollees) informing them that they are outpatients receiving observation services and are not inpatients of a hospital or critical access hospital (CAH).

Full instructions are available in Section 400, of Chapter 30 of the CMS Claims Processing Manual, available at: /Regulations-and-Guidance/Guidance/Manuals/Downloads/clm104c30.pdf (PDF)

While no changes were made to the MOON delivery or timeframe requirements, CMS made readability and design improvements for consistency with other Medicare notices. The updated version of the MOON is effective now and expires February 28, 2029.