DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

K65 Peritonitis

  • Header · not billable

K65 is not billable. The category heads 7 billable codes in FY2027: the 7 codes directly below it.

Index → code

  • Perihepatitis → K65.8
  • Serositis, multiple → K65.8
  • Saponification, mesenteric → K65.8

Where it sits

  1. Chapter 11 Diseases of the digestive system (K00-K95)
  2. K65-K6A Diseases of peritoneum, retroperitoneum and pelvis (K65-K6A)
  3. K65 Peritonitis
Billable codes
7
Subdivisions
7
CC / MCC codes
1 / 6
HCC V28 codes
7
New FY2027
0
Index entries
68

Codes in K65

  1. K65.0
    Generalized (acute) peritonitis
    BillableMCC78
    Inclusion terms 3

    Inclusion terms

    • Pelvic peritonitis (acute), male
    • Subphrenic peritonitis (acute)
    • Suppurative peritonitis (acute)
  2. K65.1
    Peritoneal abscess
    BillableMCC78
    Inclusion terms 8, Excludes2 1

    Inclusion terms

    • Abdominopelvic abscess
    • Abscess (of) omentum
    • Abscess (of) peritoneum
    • Mesenteric abscess
    • Retrocecal abscess
    • Subdiaphragmatic abscess
    • Subhepatic abscess
    • Subphrenic abscess

    Excludes2

    • pelvic abscess (extraperitoneal) (K6A.0-) K6A.0
  3. K65.2
    Spontaneous bacterial peritonitis
    BillableMCC78
    Excludes1 1

    Excludes1

    • bacterial peritonitis NOS (K65.9) K65.9
  4. K65.3
    Choleperitonitis
    BillableMCC78
    Inclusion terms 1

    Inclusion terms

    • Peritonitis due to bile
  5. K65.4
    Sclerosing mesenteritis
    BillableCC78
    Inclusion terms 5

    Inclusion terms

    • Fat necrosis of peritoneum
    • (Idiopathic) sclerosing mesenteric fibrosis
    • Mesenteric lipodystrophy
    • Mesenteric panniculitis
    • Retractile mesenteritis
  6. K65.8
    Other peritonitis
    BillableMCC78
    Inclusion terms 2

    Inclusion terms

    • Chronic proliferative peritonitis
    • Peritonitis due to urine
  7. K65.9
    Peritonitis, unspecified
    BillableMCC78
    Inclusion terms 1

    Inclusion terms

    • Bacterial peritonitis NOS

CC/MCC: as a secondary diagnosis, unless the principal diagnosis is on the code’s PDX exclusion list (MS-DRG v44 Appendix C; list on the code card).

Sources of each column.

Instructions

At K65

Excludes1

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

Use additional code

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

Code also

  • if applicable diverticular disease of intestine (K57.-) K57

Notes that also apply

Chapter 11 instructions (Excludes2 8): printed on the chapter 11 page.

Index entries

  • Choleperitoneum, choleperitonitis → K65.3
  • Perihepatitis → K65.8
  • Saponification, mesenteric → K65.8
  • Serositis, multiple → K65.8
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion) → K65.9
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)acute (generalized) → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)diaphragmatic → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)diffuse → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)disseminated → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)fibropurulent → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)general (ized) → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)pancreatic → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)purulent → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)septic → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)subdiaphragmatic → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)subphrenic → K65.0
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)suppurative → K65.0
  • Rupture, rupturedcecum (with peritonitis) → K65.0
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)abdominopelvic → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)diaphragm, diaphragmatic → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)epiploon, epiploic → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)intra-abdominal → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)intraperitoneal → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)mesentery, mesenteric → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)omentum → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)peritoneum, peritoneal (perforated) (ruptured) → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)retrocecal → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)subdiaphragmatic → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)subhepatic → K65.1
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)subphrenic → K65.1
  • Sepsis (generalized) (unspecified organism)intra-abdominal → K65.1
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)spontaneous bacterial → K65.2
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)bile, biliary → K65.3
  • Fibrosis, fibroticsclerosing mesenteric (idiopathic) → K65.4
  • Lipodystrophymesenteric → K65.4
  • Mesenteritisretractile → K65.4
  • Mesenteritissclerosing → K65.4
  • Panniculitis (nodular) (nonsuppurative)mesenteric → K65.4
  • Capsulitis (joint)hepatic → K65.8
  • Cecitiswith perforation, peritonitis, or rupture → K65.8

28 more, longer entries are not listed; the search box finds them by word.

NCHS Alphabetic Index. Index first, then the Tabular List.

Hierarchy