2027 ICD-10-CM Diagnosis Code N80.331Superficial endometriosis of the right pelvic sidewall

ICD-10-CM Codes›N00–N99›N80-N98›N80

ICD-10-CM N80.331
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

N80.331 is a billable ICD-10-CM diagnosis code for superficial endometriosis of the right pelvic sidewall. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 742 through 743, 760 through 761. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Endometriosis.

Code Identity

ICD-10-CM Code
N80.331
Billable Status
Yes — Valid for Submission
Code Describes
Superficial endometriosis of the right pelvic sidewall
Short Description
Superficial endometriosis of the right pelvic sidewall
Same as the full description in the CMS dataset.
Parent Code
N80.33
Superficial endometriosis of the pelvic sidewall

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN80-N98Noninflammatory disorders of female genital tract
CategoryN80Endometriosis
This CodeN80.331Superficial endometriosis of the right pelvic sidewall

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to N80.331: its own notes plus those printed at Chapter 14. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 14 (N00-N99) Diseases of the genitourinary system applies to 838 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name N80.331, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming N80.331: they are not reported together with it, unless the two conditions are unrelated.

  • N85 Other noninflammatory disorders of uterus, except cervix
    endometriosis (N80.-) names N80.-, which includes this code

Clinical ClassificationClinical

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

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

Clinical InformationClinical

  • Endometriosis

    a condition in which functional endometrial tissue is present outside the uterus. it is often confined to the pelvis involving the ovary, the ligaments, cul-de-sac, and the uterovesical peritoneum.

Code History & ChangesHistory

Replacement N80.331 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 2024–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About N80.331Overview

What is the ICD-10 code for superficial endometriosis of the right pelvic sidewall?

The ICD-10-CM code for superficial endometriosis of the right pelvic sidewall is N80.331 (sometimes written as N80331). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is N80.331 (Superficial endometriosis of the pelvic sidewall) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report superficial endometriosis of the right pelvic sidewall on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does N80.331 group to?

When superficial endometriosis of the right pelvic sidewall is the principal diagnosis on an inpatient stay, it groups to MS-DRG 742, 743, 760, 761, with relative weights from 0.7039 to 1.8448 depending on complications. Higher weights mean higher Medicare reimbursement.