ICD-10-CM
ICD-10 code for Peritonitis: K65.9
The ICD-10-CM index points "Peritonitis" to K65 (Peritonitis), a header that is not billable. When nothing more specific is documented, the billable code is K65.9, Peritonitis, unspecified.
Source: CDC ICD-10-CM FY2027 Alphabetic Index file dated June 16, 2026. Publisher page
Run it in Rivvi
Check every code on your export
Upload a claims or problem-list export. Rivvi flags codes that are not billable, replaced, or unspecified when a specific code exists.
Check my exportFree to start. Opens Rivvi, the AI workspace for healthcare teams.
Index subterms
A header groups codes and is not billed. A billable code is one you can report.
- K65.0acute (generalized), Generalized (acute) peritonitisBillable
- T81.61aseptic, Aseptic peritonitis due to foreign substance accidentally left during a procedureHeader
- K65.3bile, biliary, CholeperitonitisBillable
- T81.61chemical, Aseptic peritonitis due to foreign substance accidentally left during a procedureHeader
- A74.81chlamydial, Chlamydial peritonitisBillable
- P78.1congenital, Other neonatal peritonitisBillable
- K65.8chronic proliferative, Other peritonitisBillable
- K65.0diaphragmatic, Generalized (acute) peritonitisBillable
- K65.0diffuse, Generalized (acute) peritonitisBillable
- A36.89diphtheritic, Other diphtheritic complicationsBillable
- K65.0disseminated, Generalized (acute) peritonitisBillable
- K65.8eosinophilic, Other peritonitisBillable
- A18.31fibrocaseous (tuberculous), Tuberculous peritonitisBillable
- K65.0fibropurulent, Generalized (acute) peritonitisBillable
- O08.0following ectopic or molar pregnancy, Genital tract and pelvic infection following ectopic and molar pregnancyBillable
- K65.0general (ized), Generalized (acute) peritonitisBillable
- A54.85gonococcal, Gonococcal peritonitisBillable
- P78.0meconium (newborn), Perinatal intestinal perforationBillable
- P78.1neonatal, Other neonatal peritonitisBillable
- K65.0pancreatic, Generalized (acute) peritonitisBillable
- E85.0paroxysmal, familial, Non-neuropathic heredofamilial amyloidosisBillable
- E85.0periodic, familial, Non-neuropathic heredofamilial amyloidosisBillable
- K65.8proliferative, chronic, Other peritonitisBillable
- O85puerperal, postpartum, childbirth, Puerperal sepsisBillable
- K65.0purulent, Generalized (acute) peritonitisBillable
- K65.0septic, Generalized (acute) peritonitisBillable
- K65.8specified NEC, Other peritonitisBillable
- K65.2spontaneous bacterial, Spontaneous bacterial peritonitisBillable
- K65.0subdiaphragmatic, Generalized (acute) peritonitisBillable
- K65.0subphrenic, Generalized (acute) peritonitisBillable
- K65.0suppurative, Generalized (acute) peritonitisBillable
- A52.74syphilitic, Syphilis of liver and other visceraBillable
- T81.61talc, Aseptic peritonitis due to foreign substance accidentally left during a procedureHeader
- A18.31tuberculous, Tuberculous peritonitisBillable
- K65.8urine, Other peritonitisBillable
More specific codes in K65
A header groups codes and is not billed. A billable code is one you can report.
Code also
The CDC tabular list says a second code may be needed with this one. The note does not set which is listed first.
From K65. A note on a category applies to every code under it.
Code also if applicable diverticular disease of intestine (K57.-)
Use additional code
The CDC tabular list says to add the code named here after this one when it applies.
From K65. A note on a category applies to every code under it.
Use additional code (B95-B97), to identify infectious agent, if known
Excludes1
Excludes1 means these codes are not reported together.
From K65. A note on a category applies to every code under it.
- K35.2-Acute appendicitis with generalized peritonitis
- T81.6Aseptic peritonitis
- E85.0Benign paroxysmal peritonitis
- T81.6Chemical peritonitis
- A54.85Gonococcal peritonitis
- P78.0-P78.1Neonatal peritonitis
- N73.3-N73.5Pelvic peritonitis, female
- E85.0Periodic familial peritonitis
- T81.6Peritonitis due to talc or other foreign substance
- A74.81Peritonitis in chlamydia
- A36.89Peritonitis in diphtheria
- A52.74Peritonitis in syphilis (late)
- A18.31Peritonitis in tuberculosis
- O00-O07, O08.0Peritonitis with or following abortion or ectopic or molar pregnancy
- K35.-Peritonitis with or following appendicitis
- O85Puerperal peritonitis
- K68.-Retroperitoneal infections
Related conditions
Related pages
- K65.9 code detailsNotes, nearby codes, CMS-HCC group
- Category K65Every code under it
- Chapter 11Diseases of the digestive system
- ICD-10 codes by conditionA to Z
- Check a list of ICD-10 codes
- Denial code CO-11Diagnosis does not support the procedure
- Denial code CO-146Diagnosis invalid for the date of service
- HCPCS Level II code lookup
Questions
What is the ICD-10 code for Peritonitis?
The ICD-10-CM index points "Peritonitis" to K65 (Peritonitis), a header that is not billable. When nothing more specific is documented, the billable code is K65.9, Peritonitis, unspecified.
Is K65.9 billable?
Yes. K65.9 is a billable code in the FY2027 ICD-10-CM file. Use a more specific code when the record documents one.
What documentation notes apply to K65.9?
The CDC tabular list gives 17 Excludes1 notes (not coded together), 1 "use additional code" note for K65.9 and the categories above it. They are listed on this page.
What chapter is K65.9 in?
Chapter 11. Diseases of the digestive system.
When do ICD-10-CM codes change?
Every October 1, with the new fiscal year file. Some years add April 1 updates. This page uses the FY2027 file, effective October 1, 2026.