Peritonitis
Diseases of the Digestive System·Diseases of peritoneum, retroperitoneum and pelvis (K65-K6A)·category·FY 2027
7 billable codes under K65: 6 are an MCC, 1 is a CC; all map to HCC 78 (Intestinal Obstruction/Perforation).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.
Peritoneal Disorders: Your peritoneum is the tissue that lines your abdominal wall and covers most of the organs in your abdomen. A liquid, peritoneal fluid, lubricates the surface of this tissue.
Read more about peritoneal disorders on MedlinePlus · Source: MedlinePlus, National Library of Medicine
Instructional notes
Excludes1: not coded here, use a different code
- 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.-)
Code also: add a code for this too, order depends on the encounter
- if applicable diverticular disease of intestine (K57.-)
Use additional code: add a second code for this, listed after this one
- code (B95-B97), to identify infectious agent, if known
All codes under K65
K65 can't be used on a claim. Pick a billable code below; grey headings group them.
MS-DRGs
As the principal diagnosis, the billable codes under K65 group to these MS-DRGs (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.
- DRG 791 Prematurity with Major Problems (7 of 7 codes)
- DRG 793 Full Term Neonate with Major Problems (7 of 7 codes)
- DRG 371 Major Gastrointestinal Disorders and Peritoneal Infections with MCC (5 of 7 codes)
- DRG 372 Major Gastrointestinal Disorders and Peritoneal Infections with CC (5 of 7 codes)
- DRG 373 Major Gastrointestinal Disorders and Peritoneal Infections without CC/MCC (5 of 7 codes)
- DRG 393 Other Digestive System Diagnoses with MCC (2 of 7 codes)
- DRG 394 Other Digestive System Diagnoses with CC (2 of 7 codes)
- DRG 395 Other Digestive System Diagnoses without CC/MCC (2 of 7 codes)
Codes whose notes mention K65
If you are coding one of these, its note tells you to add K65 too (Code Also, Use Additional Code), code it first (Code First), or not use it together (Excludes1).
- K57 Code Also: peritonitis (K65.-)