2027 ICD-10-CM Diagnosis Code N80.399Endometriosis of the pelvic peritoneum, other specified sites, unspecified depth

ICD-10-CM Codes›N00–N99›N80-N98›N80

ICD-10-CM N80.399
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

N80.399 is a billable ICD-10-CM diagnosis code for endometriosis of the pelvic peritoneum, other specified sites, unspecified depth. 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. Coders also document this condition as endometriosis of parametrium. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Endometriosis.

Code Identity

ICD-10-CM Code
N80.399
Billable Status
Yes — Valid for Submission
Code Describes
Endometriosis of the pelvic peritoneum, other specified sites, unspecified depth
Short Description
Endometriosis of pelvic peritoneum, oth sites, unsp depth
Parent Code
N80.39
Endometriosis of other pelvic peritoneum

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN80-N98Noninflammatory disorders of female genital tract
CategoryN80Endometriosis
This CodeN80.399Endometriosis of the pelvic peritoneum, other specified sites, unspecified depth

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Endometriosis of parametrium

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to N80.399: 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 N80.399, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming N80.399: 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

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

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 N80.399 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 N80.399Overview

Is N80.399 (Endometriosis of other pelvic peritoneum) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report endometriosis of the pelvic peritoneum, other specified sites, unspecified depth on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does N80.399 group to?

When endometriosis of the pelvic peritoneum, other specified sites, unspecified depth 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.