Sources

Everything on this site comes from the files below, downloaded from the servers of the agencies that publish them and pinned by their SHA-256 hash: a build with any other file stops. The NCHS ICD-10-CM page and the CMS ICD-10 page list the current editions.

Files

Attribution

ICD-10-CM is the United States clinical modification of ICD-10. The World Health Organization (WHO) owns and publishes ICD-10 and authorized the National Center for Health Statistics (NCHS), part of CDC, to develop ICD-10-CM. Code titles, notes, 7th-character tables and Index entries are printed as NCHS publishes them, without translation or change. MS-DRG, Medicare Code Editor, POA and CMS-HCC data are works of the Centers for Medicare & Medicaid Services (CMS). Neither agency nor WHO endorses this site.

We do not use AHA Coding Clinic, AAPC, AMA CPT or other licensed content.

Rules quoted in the guides come from the ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, cited by section.

Versions

Classification: ICD-10-CM FY2027, effective October 1, 2026 through September 30, 2027. Previous edition used for the comparison: FY2026. MS-DRG Definitions Manual v44.0 and Medicare Code Editor v44.0 (FY2027 final rule). CMS-HCC V28 from the 2027 Initial ICD-10-CM Mappings; that file covers codes valid in FY2025–FY2026, so codes new in FY2027 have no HCC there yet, and a code that became a header in FY2027 shows none.

CC/MCC comes from Appendix C of the MS-DRG manual: Part 1 (the CC or MCC level of each code and its principal-diagnosis exclusion list) and Part 2 (codes that are an MCC only if the patient is discharged alive). Part 3 (CC/MCC exclusions that apply only in certain MS-DRGs) is not shown on code pages.

The NCHS file server was last checked for an update of FY2027 (such as an April 1 update) on October 24, 2026: none published.