K65 Peritonitis

Category / Non-billable header 7 subcodes

Block: Diseases of peritoneum and retroperitoneum (K65-K6A)

Excludes 1 (cannot be coded 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.-)

Subcodes

Subcodes are listed below for reference. Detail pages are not available for chapters 11–22.

Code Description Billable
K65..0 Generalized (acute) peritonitis Yes
K65..1 Peritoneal abscess Yes
K65..2 Spontaneous bacterial peritonitis Yes
K65..3 Choleperitonitis Yes
K65..4 Sclerosing mesenteritis Yes
K65..8 Other peritonitis Yes
K65..9 Peritonitis, unspecified Yes

Last reviewed: September 2026