2026 ICD-10-CM Diagnosis Code N80.40Endometriosis of rectovaginal septum, unspecified involvement of vagina

ICD-10-CM Codes›N00–N99›N80-N98›N80

ICD-10-CM N80.40
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N80.40 is a billable ICD-10-CM diagnosis code for endometriosis of rectovaginal septum, unspecified involvement of vagina. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 742 through 743, 760 through 761. Coders also document this condition as endometriosis of rectovaginal septum. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Endometriosis.

Code Identity

ICD-10-CM Code
N80.40
Billable Status
Yes — Valid for Submission
Code Describes
Endometriosis of rectovaginal septum, unspecified involvement of vagina
Short Description
Endometriosis of rectovaginal septum, unsp invl of vagina
Parent Code
N80.4
Endometriosis of rectovaginal septum and vagina

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN80-N98Noninflammatory disorders of female genital tract
CategoryN80Endometriosis
This CodeN80.40Endometriosis of rectovaginal septum, unspecified involvement of vagina

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Endometriosis of rectovaginal septum
  • Endometriosis of vagina

Tabular List NotesGuidance

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

Inclusion Terms

  • Endometriosis of the rectovaginal septum, NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Endometriosis
      • rectovaginal septum

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 N80.40 replaces the following previously assigned code(s):

  • N80.3 - Endometriosis of pelvic peritoneum
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 N80.40Overview

Is N80.40 (Endometriosis of rectovaginal septum and vagina) a billable code?

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

What MS-DRG does N80.40 group to?

When endometriosis of rectovaginal septum, unspecified involvement of vagina is the principal diagnosis on an inpatient stay, it groups to MS-DRG 742, 743, 760, 761, with relative weights from 0.5696 to 1.8348 depending on complications. Higher weights mean higher Medicare reimbursement.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.