What does ICD-10 code K65 mean?

ICD-10 code K65 is the standardized code used for peritonitis in medical records and coding systems.

When is ICD-10 code K65 used?

Doctors, hospitals, and insurers may use ICD-10 code K65 when recording peritonitis in a standardized format. This entry may also act as a broader category that points toward more specific child codes.

Does ICD-10 code K65 confirm a diagnosis?

No. A code helps standardize documentation and claims, but it should not be read as a substitute for a clinician's full assessment.

ICD10

ICD-10 Code K65: Peritonitis

Name: ICD-10 Code K65: Peritonitis
Creator: HealthAssure Clinical Team
Published: 2026-05-21T06:15:54.135Z

K65 is an ICD-10 diagnosis entry used to group records related to Peritonitis. You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen. ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the digestive system (K00-K95).

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the digestive system (K00-K95).

When is it used?

May be used when a clinician documents peritonitis in a patient's medical record.
May appear in hospital records, claims, referrals, and clinical documentation.
This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.

What it does not mean

A code alone does not explain severity, treatment plan, or outcome.
A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
This entry may represent a broader category rather than the most specific billable code.

Code hierarchy

chapter

11Diseases of the digestive system (K00-K95)

block

K65-K68Diseases of peritoneum and retroperitoneum

currentK65-K68

Official coding notes

Applicable to

code (B95-B97), to identify infectious agent, if known

Excludes1 (do not code together)

acute appendicitis with generalized peritonitis (K35.2-)
aseptic peritonitis (T81.6)
benign paroxysmal peritonitis (E85.0)
chemical peritonitis (T81.6)
gonococcal peritonitis (A54.85)
neonatal peritonitis (P78.0-P78.1)
pelvic peritonitis, female (N73.3-N73.5)
periodic familial peritonitis (E85.0)
peritonitis due to talc or other foreign substance (T81.6)
peritonitis in chlamydia (A74.81)
peritonitis in diphtheria (A36.89)
peritonitis in syphilis (late) (A52.74)
peritonitis in tuberculosis (A18.31)
peritonitis with or following abortion or ectopic or molar pregnancy (O00-O07, O08.0)
peritonitis with or following appendicitis (K35.-)
puerperal peritonitis (O85)
retroperitoneal infections (K68.-)

Use additional code

code (B95-B97), to identify infectious agent, if known

Code also

if applicable diverticular disease of intestine (K57.-)

Where you may see this code

You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.

Related specialists

GastroenterologistGeneral Physician

Sibling codes

K66Other disorders of peritoneum K67Disorders of peritoneum in infectious diseases classified elsewherebillable K68Disorders of retroperitoneum

Coding guidelines

Compatibility

Legacy code aligns to an official FY 2026 category. Frontend should resolve to the official category page and surface the billable child codes.

Legacy codes

K65

Replacement codes

K65.0 — Generalized (acute) peritonitisK65.1 — Peritoneal abscessK65.2 — Spontaneous bacterial peritonitisK65.3 — CholeperitonitisK65.4 — Sclerosing mesenteritisK65.8 — Other peritonitisK65.9 — Peritonitis, unspecified

Common synonyms

Peritonitis

Frequently asked questions

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.