K65
ICD-10Non-billable categoryPeritonitis
Official ICD-10-CM descriptor (FY2026)
Peritonitis
K65 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.
Excludes1
Not coded here. An Excludes1 code should never be reported at the same time as the code above it.
- 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
Report an additional code to identify the associated condition.
- code (B95-B97), to identify infectious agent, if known
Code also
Two codes may be needed; sequencing depends on the reason for the encounter.
- if applicable diverticular disease of intestine (K57.-)
More specific codes under K65
Where this code sits
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ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.