ICD-10-CM 2027 diagnosis code
K65.1Peritoneal abscess
K65.1 is a valid, billable ICD-10-CM code for peritoneal abscess. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Looking up by condition? See ICD-10 code for Subphrenic abscess.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About K65.1
K65.1 is the ICD-10-CM diagnosis code for peritoneal abscess. It belongs to category K65 (peritonitis), block K65-K6A (diseases of peritoneum, retroperitoneum and pelvis) and chapter 11 (diseases of the digestive system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within K65 (peritonitis), K65.1 is specifically for peritoneal abscess. Related codes cover generalized (acute) peritonitis (K65.0), spontaneous bacterial peritonitis (K65.2), Choleperitonitis (K65.3), sclerosing mesenteritis (K65.4), other peritonitis (K65.8) and unspecified (K65.9).
The conditions in its Excludes2 note aren't part of K65.1, but may be coded alongside it if the patient has both: pelvic abscess (extraperitoneal) (K6A.0-).
Use an additional code (B95-B97), to identify infectious agent, if known.
As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 371 (Major Gastrointestinal Disorders and Peritoneal Infections with MCC, relative weight 1.7089), DRG 372 (Major Gastrointestinal Disorders and Peritoneal Infections with CC, relative weight 0.9964), DRG 373 (Major Gastrointestinal Disorders and Peritoneal Infections without CC/MCC, relative weight 0.6941), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 06 (Diseases and Disorders of the Digestive System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 567.22 (peritoneal abscess).
Coding notes
- Abdominopelvic abscess
- Abscess (of) omentum
- Abscess (of) peritoneum
- Mesenteric abscess
- Retrocecal abscess
- Subdiaphragmatic abscess
- Subhepatic abscess
- Subphrenic abscess
- pelvic abscess (extraperitoneal) (K6A.0-)
Notes that apply from higher levels
Instructions written at a parent level also apply to K65.1.
› From K65 Peritonitis
- 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.-)
- if applicable diverticular disease of intestine (K57.-)
Broader instructions also apply from Chapter 11: Diseases of the digestive system.
Alphabetic index entries
18 entriesTerms in the official ICD-10-CM index that lead to K65.1.
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › abdomen, abdominal › cavity
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › abdominopelvic
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › diaphragm, diaphragmatic
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › epiploon, epiploic
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › intra-abdominal
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › intraperitoneal
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › mesentery, mesenteric
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › omentum
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › pelvis, pelvic › female - › peritoneal
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › pelvis, pelvic › male › peritoneal
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › peritoneum, peritoneal (perforated) (ruptured)
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › peritoneum, peritoneal (perforated) (ruptured) › pelvic › male
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › retrocecal
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › subdiaphragmatic
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › subhepatic
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › subphrenic
- Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion) › with or following › abscess
- Sepsis (generalized) (unspecified organism) › intra-abdominal
Codes whose notes reference K65.1
- K6A.0Excludes2
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 06 · Diseases and Disorders of the Digestive System
MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period
MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period
ICD-9-CM equivalent
Converter →- 567.22Peritoneal abscessexact
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about K65.1
Is K65.1 billable?
- Yes. K65.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K65.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K65.1 as a principal diagnosis.
Is K65.1 a CC or MCC?
- K65.1 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does K65.1 group to?
- K65.1 is used in the MS-DRG v44.0 logic for MS-DRG 371 (Major Gastrointestinal Disorders and Peritoneal Infections with MCC), MS-DRG 372 (Major Gastrointestinal Disorders and Peritoneal Infections with CC), MS-DRG 373 (Major Gastrointestinal Disorders and Peritoneal Infections without CC/MCC), MS-DRG 791 (Prematurity with Major Problems) and MS-DRG 793 (Full Term Neonate with Major Problems). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for K65.1?
- The CMS General Equivalence Mappings map K65.1 to ICD-9-CM 567.22.