Does the FY2027 ERRATA change ICD-10-CM diagnosis codes?

No—not by itself. On the CMS ICD-10 files page checked October 10, 2026, the link labelled 2027 ERRATA appears beneath 2027 ICD-10-PCS files. Its two-page PDF is titled “ERRATA - ICD-10 MS-DRGs Version 44 Effective October 1, 2026” and says CMS is implementing two additional ICD-10-PCS procedure codes. It describes the accompanying MS-DRG Grouper and Medicare Code Editor context. That source is not a notice that a U.S. ICD-10-CM diagnosis code was added, deleted or retitled.

This is a question about source provenance, not a patient-specific coding decision. ICD-10-CM is the U.S. diagnosis classification; ICD-10-PCS is the inpatient procedure classification. The same FY2027 label on a CMS page does not make their files interchangeable. Our date-boundary guide explains why the applicable release and encounter or discharge period also belong in a source check.

The CMS page groups files by classification. Its 2027 ICD-10-CM files section lists the POA-exempt file, conversion table, code descriptions, addendum, code tables with Tabular List and Index, and diagnosis guidelines. The next 2027 ICD-10-PCS files section lists the ERRATA PDF alongside PCS tables, codes, addendum and PCS guidelines. On this page the diagnosis files are described for October 1, 2026–September 30, 2027 encounters and discharges; the displayed PCS group is described for October 1, 2026–March 31, 2027 discharges. Read each heading rather than transferring one period to the other.

The table records the source family, not a claim that every file has the same update cycle. The versioned FY2027 source library keeps the CM files grouped for a repeatable review.

The CMS PDF states that two additional procedure codes bring its count of new FY2027 ICD-10-PCS codes to 103 and that the Version 44 MS-DRG Grouper accommodates those two additions for discharges on or after October 1, 2026. Its first page calls the listed entries procedure codes; its second page labels a change summary as ICD-10-PCS Code FY 2027 Totals. The document also discusses claim edits and DRG assignment. Those payment-system details should not be converted into a diagnosis-code announcement or a payment prediction for a particular case.

The PDF’s title and first-page wording are stronger evidence of scope than the short “ERRATA” link text. The server returned a Last-Modified header of August 21, 2026 when checked on October 10; that is a file-serving timestamp, not a claimed new October diagnosis revision. If CMS publishes a later file, recheck its own title, effective date, classification and contents. Avoid treating a screenshot of the link label as a complete change notice.

1. Fix the applicable diagnosis release. CDC/NCHS says the October 1, 2026 FY2027 ICD-10-CM release applies to healthcare services through September 30, 2027, subject to any later official update. Record the service or discharge context.
2. Find a CM source with the exact change. Start at the official FY2027 diagnosis-file folder or the CMS 2027 ICD-10-CM section. Note the file name and observed date. The CDC folder showed the FY2027 CM addenda and full Table/Index files dated June 16, 2026 when checked October 10.
3. Match the change to the full entry. If the CM addenda identifies a relevant addition, deletion or wording change, inspect the complete released CM Tabular List and Index. A change record alone is not the whole current instruction.
4. State only what the files support. Record the classification, FY2027 release, exact file, affected entry and effective date. If the claim concerns a later correction, find and cite that later official CM file before describing it as active. A PCS errata label cannot fill that evidence gap.

Our addenda checklist and Chapter 1 change example show how to connect a CM change line to its full released Tabular context. A qualified coder must review a real diagnosis assignment.

The absence of a CM errata link in the CMS section as observed October 10 does not prove that no future ICD-10-CM correction can appear. It establishes only that this particular linked ERRATA is a PCS and MS-DRG document. A future diagnosis-file update would need its own primary CM source and effective date. Likewise, the CMS PDF’s mention of diagnosis codes as one input to an MS-DRG does not change the classification of the two new codes it identifies.

The reusable takeaway is CMS CM section versus PCS section → exact document title and effective date → CDC/NCHS CM release files → full entry if a diagnosis change is claimed. Keep this trail close to the conclusion so a reader can verify it. The proposal-versus-release guide explains another common status trap: a discussed future term is not an applicable current code.

When reviewing a saved link or document on another device, retain “ICD-10-CM FY2027” or “ICD-10-PCS FY2027” beside its URL. ICD Code Hub’s Android, iPhone and Mac apps provide access to available versioned reference routes, but the CDC/NCHS diagnosis files and the CMS classification-specific file groups are the sources for this provenance check. The shared store links below point to the live listings.

This guide makes no code selection, clinical judgment or payment determination. For a real record, use the complete applicable classification, official guidance and qualified review.