ICD-10 Code for Peritonitis
Also indexed as (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)
The ICD-10-CM code for peritonitis is K65.9 — Peritonitis, unspecified. This is the code the Alphabetic Index gives for peritonitis with no further qualifier, valid for FY2027 (October 1, 2026 – September 30, 2027).
BillableUnspecified
K65.9 is billable but unspecified. If the documentation names a type, site or cause, one of the more specific codes below is likely expected.
Which peritonitis code should you use?
The Alphabetic Index lists 35 codes under Peritonitis. Which one applies depends on the qualifier documented in the record — the type, site, cause, or associated condition. Find the qualifier below, then verify the code in the Tabular List before using it.
By type
| acute | K65.0 | Generalized (acute) peritonitis | |
| aseptic | T81.61 | Aseptic peritonitis due to foreign substance accidentally left during a procedure | not billable |
| bile, biliary | K65.3 | Choleperitonitis | |
| chemical | T81.61 | Aseptic peritonitis due to foreign substance accidentally left during a procedure | not billable |
| chlamydial | A74.81 | Chlamydial peritonitis | |
| congenital | P78.1 | Other neonatal peritonitis | |
| chronic proliferative | K65.8 | Other peritonitis | |
| diaphragmatic | K65.0 | Generalized (acute) peritonitis | |
| diffuse | K65.0 | Generalized (acute) peritonitis | |
| diphtheritic | A36.89 | Other diphtheritic complications | |
| disseminated | K65.0 | Generalized (acute) peritonitis | |
| eosinophilic | K65.8 | Other peritonitis | |
| fibrocaseous | A18.31 | Tuberculous peritonitis | |
| fibropurulent | K65.0 | Generalized (acute) peritonitis | |
| following ectopic or molar pregnancy | O08.0 | Genital tract and pelvic infection following ectopic and molar pregnancy | |
| general | K65.0 | Generalized (acute) peritonitis | |
| gonococcal | A54.85 | Gonococcal peritonitis | |
| meconium | P78.0 | Perinatal intestinal perforation | |
| neonatal | P78.1 | Other neonatal peritonitis | |
| pancreatic | K65.0 | Generalized (acute) peritonitis | |
| paroxysmal, familial | E85.0 | Non-neuropathic heredofamilial amyloidosis | |
| periodic, familial | E85.0 | Non-neuropathic heredofamilial amyloidosis | |
| proliferative, chronic | K65.8 | Other peritonitis | |
| puerperal, postpartum, childbirth | O85 | Puerperal sepsis | |
| purulent | K65.0 | Generalized (acute) peritonitis | |
| septic | K65.0 | Generalized (acute) peritonitis | |
| specified NEC | K65.8 | Other peritonitis | |
| spontaneous bacterial | K65.2 | Spontaneous bacterial peritonitis | |
| subdiaphragmatic | K65.0 | Generalized (acute) peritonitis | |
| subphrenic | K65.0 | Generalized (acute) peritonitis | |
| suppurative | K65.0 | Generalized (acute) peritonitis | |
| syphilitic | A52.74 | Syphilis of liver and other viscera | |
| talc | T81.61 | Aseptic peritonitis due to foreign substance accidentally left during a procedure | not billable |
| tuberculous | A18.31 | Tuberculous peritonitis | |
| urine | K65.8 | Other peritonitis |
Peritonitis with or following
| abscess | K65.1 | Peritoneal abscess | |
| diverticular disease | K57.80 | Diverticulitis of intestine, part unspecified, with perforation and abscess without bleeding | |
| appendicitis › with perforation or rupture | K35.32 | Acute appendicitis with perforation, localized peritonitis, and gangrene, without abscess | |
| appendicitis › generalized | K35.209 | Acute appendicitis with generalized peritonitis, without abscess, unspecified as to perforation | |
| appendicitis › localized | K35.30 | Acute appendicitis with localized peritonitis, without perforation or gangrene | |
| diverticular disease › with bleeding | K57.81 | Diverticulitis of intestine, part unspecified, with perforation and abscess with bleeding | |
| diverticular disease › large intestine | K57.20 | Diverticulitis of large intestine with perforation and abscess without bleeding | |
| diverticular disease › small intestine | K57.00 | Diverticulitis of small intestine with perforation and abscess without bleeding | |
| diverticular disease › ectopic or molar pregnancy | O08.0 | Genital tract and pelvic infection following ectopic and molar pregnancy | |
| diverticular disease › large intestine › with › bleeding | K57.21 | Diverticulitis of large intestine with perforation and abscess with bleeding | |
| diverticular disease › large intestine › with › small intestine | K57.40 | Diverticulitis of both small and large intestine with perforation and abscess without bleeding | |
| diverticular disease › small intestine › with › bleeding | K57.01 | Diverticulitis of small intestine with perforation and abscess with bleeding | |
| diverticular disease › small intestine › with › large intestine | K57.40 | Diverticulitis of both small and large intestine with perforation and abscess without bleeding | |
| diverticular disease › large intestine › with › small intestine › with bleeding | K57.41 | Diverticulitis of both small and large intestine with perforation and abscess with bleeding | |
| diverticular disease › small intestine › with › large intestine › with bleeding | K57.41 | Diverticulitis of both small and large intestine with perforation and abscess with bleeding |
Peritonitis due to
| bile | K65.3 | Choleperitonitis | |
| talc | T81.61 | Aseptic peritonitis due to foreign substance accidentally left during a procedure | not billable |
| urine | K65.8 | Other peritonitis | |
| foreign › body or object accidentally left during a procedure | T81.599 | Other complications of foreign body accidentally left in body following unspecified procedure | not billable |
| foreign › substance accidentally left during a procedure | T81.61 | Aseptic peritonitis due to foreign substance accidentally left during a procedure | not billable |
Peritonitis eosinophilic
| acute | K65.0 | Generalized (acute) peritonitis |
Peritonitis neonatal
| meconium | P78.0 | Perinatal intestinal perforation |
Peritonitis paroxysmal, familial
| benign | E85.0 | Non-neuropathic heredofamilial amyloidosis |
Peritonitis pelvic
Peritonitis syphilitic
| congenital | A50.08 | Early visceral congenital syphilis |
Index terms and codes are reproduced from the official ICD-10-CM FY2027 release. The Alphabetic Index is a finding aid — a code must always be verified in the Tabular List before it is reported. Data sources