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Outpatient Prospective Payment System (OPPS) Addendums Updates A, B, D1, and E

Updates to the Outpatient Prospective Payment System (OPPS) and Integrated Outpatient Code Editor (I/OCE) are released on a quarterly basis Each update is an important resources for staying current is the set of OPPS addenda—particularly Addendum A and Addendum B.

What Are Addendum A and Addendum B?

Addendum A and Addendum B are key reference documents published on the OPPS website each quarter. Together, they provide a comprehensive overview—or “snapshot”—of how outpatient services are classified and paid at the beginning of each quarter.

These addenda include critical information such as:

  • HCPCS codes used to report services
  • Status indicators, which define how services are paid under OPPS
  • Ambulatory Payment Classifications (APCs) assigned to each code
  • OPPS payment rates associated with those services

OPPS is updated regularly to reflect policy changes, payment adjustments, and coding updates. The quarterly releases of Addendum A and Addendum B incorporate these changes and mirror the updates made in the OPPS Pricer, which is used to calculate Medicare payments.

This means:

  • Payment rates may change
  • APC groupings may be reassigned
  • Status indicators may be updated, affecting whether and how services are paid

Staying current with these updates helps ensure accurate billing and reduces the risk of claim errors or unexpected payment differences.

OPPS and I/OCE Quarterly Updates

To view official OPPS and I/OCE quarterly updates search the CMS Transmittals

Search using key words such as " Update of the Hospital Outpatient Prospective Payment System (OPPS)" or " Integrated Outpatient Code Editor (I/OCE) Specifications"

OPPS and IOCE Quarterly update Medicare Learning Network (MLN) articles:

MLN Matters article MM14477 - Hospital Outpatient Prospective Payment System: July 2026 Update

To access the OPPS addenda, start by going to the Quarterly Addenda Updates webpage. From there, follow these basic steps outlines below: 

Addendum A - APC groups and OPPS payment rates 

  • After clicking on the hyperlink above, choose the appropriate Release Date from the options listed.
  • Then on the "Details for title: Month 20XX" page, click on Addendum A under Related Links.
  • After you choose Accept and open, a box will appear with all the addenda available.
  • Choose either version of Addendum A (.xlsx or .csv) and the file will open. 

Addendum B - HCPCS codes and their status indicators 

  • After clicking on the hyperlink above, choose the appropriate Release Date from the options listed.
  • Then on the "Details for title: Month 20XX" page, click on Addendum B under Related Links.
  • After you choose Accept and open, a box will appear with all the addenda available.
  • Choose either version of Addendum B (.xlsx or .csv) and the file will open.

Addendum D1 - Payment status indicators for the Hospital Outpatient Prospective Payment System 

  • After clicking on the hyperlink above, choose the Regulation number for the appropriate Final Rulemaking year requested, CMS-xxxx-FC.
  • Scroll to the bottom of the page. Under related links choose “20XX NFRM OPPS Addenda” from the options listed.
  • After you choose Accept and open, a box will appear with all the addenda available.
  • Choose either version of 20XX NFRM addendum D1 (.xlsx or .csv) and the file will open. 

Addendum E - Inpatient only procedure codes 

  • After clicking on the hyperlink above, choose the Regulation number for the appropriate Final Rulemaking year requested, CMS-xxxx-FC.
  • Choose “20XX NFRM OPPS Addenda” from the options listed.
  • After you choose Accept and open, a box will appear with all the addenda available.
  • Choose either version of 20XX NFRM Addendum E (.xlsx or .csv) and the file will open. 

*not all-inclusive list