How to read a FY2027 ICD-10-CM addendum revision: an E29.1 example

A FY2027 addendum is a change record, not the complete code book. In the CDC/NCHS FY2027 addenda ZIP, the Tabular List PDF shows “No Change” for E29.1, titled “Testicular hypofunction,” then revises one inclusion term from “5-delta-Reductase deficiency (with male pseudohermaphroditism)” to “5-Alpha-reductase deficiency (with male pseudohermaphroditism).” The addendum labels the old and new text explicitly. It does not label E29.1 itself as added or deleted.

That is the useful distinction: the wording of an inclusion term changed at an existing entry. The full FY2027 E29.1 reference page is where you check the current term, neighboring terms, and all instructions together. This is a reference-navigation example, not advice to assign E29.1 to any patient.

1. Open the CDC/NCHS ICD-10-CM files page and choose the October 1, 2026 FY2027 release. CDC states that this release covers services from October 1, 2026, through September 30, 2027 and replaces the April 2026 FY2026 release.
2. Download icd10cm-addenda-2027.zip. Inside it, open icd10cm-tabular-addenda-2027.pdf. The E29.1 entry is in Chapter 4, under E20–E35 and E29; the “Revise from” and “Revise to” pair is visible there.
3. Open the complete FY2027 Table and Index ZIP, or navigate to the versioned E29.1 page. In the FY2027 Tabular List XML, the new phrase is an inclusion term under E29.1, alongside other terms and instructions.
4. For a real lookup, start from documented language in the FY2027 Alphabetic Index, then verify the full Tabular List entry and applicable FY2027 guidelines. The CMS guidelines explain why Index and Tabular verification must be used together.

The full file path matters because a highlighted addendum line, a search snippet, or an isolated code title may omit surrounding instructions. Our broader addenda checklist covers the other file types and review order.

This comparison describes the published files. It does not establish that every older record using the former phrase has the same clinical meaning, or that the revised phrase alone justifies a diagnosis code. Those questions depend on documentation and qualified review. The FY2027 official coding guidelines are a companion to the classification, not a replacement for the complete entry.

Addenda can identify an added code, a deleted code, a revised term, or a changed instruction. They are efficient for finding a change, but they are intentionally narrower than the current Tabular List. In this example, the revised term sits beneath an unchanged code and title; the full entry still carries its own hierarchy and notes. A workflow that treats every “Revise” marker as a new code would misread the document.

Keep a short audit trail for release reviews: the classification name, fiscal year, addenda filename, the exact entry, the full Tabular List page, and the applicable date. The October 1 release-boundary guide helps distinguish FY2026 from FY2027 work. If the updated term raises a condition-specific coding question, send it through a qualified review process rather than inferring an assignment from this educational example.

When saving or sharing a reference, include the FY2027 release and the full entry URL. ICD Code Hub’s iPhone, Android, and Mac apps can help you reopen the versioned reference while working away from the website. Check the current source and complete notes before applying a saved entry. The FY2027 source library links back to the official release files.