2026 ICD-10-CM Diagnosis Code N80.549Endometriosis of the appendix, unspecified depth

ICD-10-CM Codes›N00–N99›N80-N98›N80

ICD-10-CM N80.549
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N80.549 is a billable ICD-10-CM diagnosis code for endometriosis of the appendix, unspecified depth. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 391 through 392. Coders also document this condition as endometriosis of appendix. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Endometriosis.

Code Identity

ICD-10-CM Code
N80.549
Billable Status
Yes — Valid for Submission
Code Describes
Endometriosis of the appendix, unspecified depth
Short Description
Endometriosis of the appendix, unspecified depth
Same as the full description in the CMS dataset.
Parent Code
N80.54
Endometriosis of the appendix

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN80-N98Noninflammatory disorders of female genital tract
CategoryN80Endometriosis
This CodeN80.549Endometriosis of the appendix, unspecified depth

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Endometriosis of appendix
  • Endometriosis of large intestine

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Endometriosis of the appendix NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR GEN019
Endometriosis
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement N80.549 replaces the following previously assigned code(s):

  • N80.5 - Endometriosis of intestine
FY 2023AddedAdded to the ICD-10-CM code setEffective October 1, 2022.
FY 2024–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About N80.549Overview

What is the ICD-10 code for endometriosis of the appendix, unspecified depth?

The ICD-10-CM code for endometriosis of the appendix, unspecified depth is N80.549 (sometimes written as N80549). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is N80.549 (Endometriosis of the appendix) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report endometriosis of the appendix, unspecified depth on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does N80.549 group to?

When endometriosis of the appendix, unspecified depth is the principal diagnosis on an inpatient stay, it groups to MS-DRG 391, 392, with relative weights from 0.7796 to 1.2683 depending on complications. Higher weights mean higher Medicare reimbursement.