K91.850 ICD-10-CM Code: Pouchitis

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for K91.850 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on K91.850 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for K91.850

MedCoder structured workflow — derived from this code’s own official record

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Official instructions as workflow

• Excludes2 — not part of K91.850(7 notes)

  Coding workflow: The conditions named in this note are not included in K91.850. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareK94, K95, K28, K68.11, K52.0, K62.7

  See the official tabular notes · Guidelines I.A.12.b

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Indexed Clinical Terms (3)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Inflammation, inflamed, inflammatory (with exudation), ileoanalpouch (internal)
• Inflammation, inflamed, inflammatory (with exudation), intestinal pouch
• Pouchitis

Official Coding Guidelines

No excerpt in the ICD-10-CM Official Guidelines names this code specifically. Its chapter carries only this chapter-wide note:

Don’t confuse K91.850 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of K91.850 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• K94— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of complications of artificial opening of digestive system adds K94; it is not part of this code and both may be reported when both are documented.

  Full comparison: K91.850 vs K94 →

• K95— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of complications of bariatric procedures adds K95; it is not part of this code and both may be reported when both are documented.

  Full comparison: K91.850 vs K95 →

• K28— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of gastrojejunal ulcer adds K28; it is not part of this code and both may be reported when both are documented.

  Full comparison: K91.850 vs K28 →

• K68.11— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of postprocedural (radiation) retroperitoneal abscess adds K68.11; it is not part of this code and both may be reported when both are documented.

  Full comparison: K91.850 vs K68.11 →

• K52.0— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of radiation colitis adds K52.0; it is not part of this code and both may be reported when both are documented.

  Full comparison: K91.850 vs K52.0 →

• K62.7— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of radiation proctitis adds K62.7; it is not part of this code and both may be reported when both are documented.

  Full comparison: K91.850 vs K62.7 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name K91.850 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes2 note: T81 — Complications of procedures, not elsewhere classified (via K91.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 68 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 5 MS-DRGs: DRG 393 (MDC 06), DRG 394 (MDC 06), DRG 395 (MDC 06), DRG 791 (MDC 15), DRG 793 (MDC 15).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):DIG024 — Postprocedural or postoperative digestive system complication (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

H95.811 — Postprocedural stenosis of right external ear canal, H95.812 — Postprocedural stenosis of left external ear canal, H95.813 — Postprocedural stenosis of external ear canal, bilateral, H95.819 — Postprocedural stenosis of unspecified external ear canal, H95.88 — Other intraoperative complications and disorders of the ear and mastoid process, not elsewhere classified, H95.89 — Other postprocedural complications and disorders of the ear and mastoid process, not elsewhere classified, I97.3 — Postprocedural hypertension, K91.81 — Other intraoperative complications of digestive system, K91.82 — Postprocedural hepatic failure, K91.83 — Postprocedural hepatorenal syndrome, K91.858 — Other complications of intestinal pouch, K91.86 — Retained cholelithiasis following cholecystectomy, K91.89 — Other postprocedural complications and disorders of digestive system, K94.20 — Gastrostomy complication, unspecified, K94.21 — Gastrostomy hemorrhage, K94.22 — Gastrostomy infection, K94.23 — Gastrostomy malfunction, K94.29 — Other complications of gastrostomy, K94.30 — Esophagostomy complications, unspecified, K94.31 — Esophagostomy hemorrhage, +47 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Artificial Openings for Feeding or Elimination) for risk-adjusted payment.

K91.858 — Other complications of intestinal pouch, K94.00 — Colostomy complication, unspecified, K94.01 — Colostomy hemorrhage, K94.02 — Colostomy infection, K94.03 — Colostomy malfunction, K94.09 — Other complications of colostomy, K94.10 — Enterostomy complication, unspecified, K94.11 — Enterostomy hemorrhage, K94.12 — Enterostomy infection, K94.13 — Enterostomy malfunction, K94.19 — Other complications of enterostomy, K94.20 — Gastrostomy complication, unspecified, K94.21 — Gastrostomy hemorrhage, K94.22 — Gastrostomy infection, K94.23 — Gastrostomy malfunction, K94.29 — Other complications of gastrostomy, K94.30 — Esophagostomy complications, unspecified, K94.31 — Esophagostomy hemorrhage, K94.32 — Esophagostomy infection, K94.33 — Esophagostomy malfunction, +20 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Postprocedural or postoperative digestive system complication).

K91.5 — Postcholecystectomy syndrome, K91.61 — Intraoperative hemorrhage and hematoma of a digestive system organ or structure complicating a digestive system procedure, K91.62 — Intraoperative hemorrhage and hematoma of a digestive system organ or structure complicating other procedure, K91.71 — Accidental puncture and laceration of a digestive system organ or structure during a digestive system procedure, K91.72 — Accidental puncture and laceration of a digestive system organ or structure during other procedure, K91.81 — Other intraoperative complications of digestive system, K91.82 — Postprocedural hepatic failure, K91.83 — Postprocedural hepatorenal syndrome, K91.840 — Postprocedural hemorrhage of a digestive system organ or structure following a digestive system procedure, K91.841 — Postprocedural hemorrhage of a digestive system organ or structure following other procedure, K91.858 — Other complications of intestinal pouch, K91.86 — Retained cholelithiasis following cholecystectomy, K91.870 — Postprocedural hematoma of a digestive system organ or structure following a digestive system procedure, K91.871 — Postprocedural hematoma of a digestive system organ or structure following other procedure, K91.872 — Postprocedural seroma of a digestive system organ or structure following a digestive system procedure, K91.873 — Postprocedural seroma of a digestive system organ or structure following other procedure, K91.89 — Other postprocedural complications and disorders of digestive system, K94.00 — Colostomy complication, unspecified, K94.01 — Colostomy hemorrhage, K94.02 — Colostomy infection, +28 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Inflammation, inflamed, inflammatory”; these codes share that main term but sit in a different category of the Tabular List.

K05.11 — Chronic gingivitis, non-plaque induced (gum, nonplaque induced), K12.1 — Other forms of stomatitis (mouth), K13.0 — Diseases of lips (lip), K14.0 — Glossitis (tongue), K29.80 — Duodenitis without bleeding (duodenum), K29.81 — Duodenitis with bleeding (duodenum, with bleeding), K51.40 — Inflammatory polyps of colon without complications (polyp, colon), K62.89 — Other specified diseases of anus and rectum (rectum), K73.9 — Chronic hepatitis, unspecified (liver, chronic), K75.0 — Abscess of liver (liver, suppurative), L08.82 — Omphalitis not of newborn (navel), L08.9 — Local infection of the skin and subcutaneous tissue, unspecified (skin), M13.169 — Monoarthritis, not elsewhere classified, unspecified knee (knee), M27.2 — Inflammatory conditions of jaws (jaw), M27.3 — Alveolitis of jaws (alveoli, teeth), M46.1 — Sacroiliitis, not elsewhere classified (joint NEC, sacroiliac), N41.8 — Other inflammatory diseases of prostate (prostate, specified type NEC), N48.29 — Other inflammatory disorders of penis (penis), N49.1 — Inflammatory disorders of spermatic cord, tunica vaginalis and vas deferens (vas deferens), N49.2 — Inflammatory disorders of scrotum (scrotum), +62 more

Contextual Map

Every relationship of K91.850 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run K91.850 with this related code in Claim Check

Hierarchy

• K00-K95 — Chapter 11: Diseases of the Digestive System (K00-K95) (K00-K95)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K90-K95 — Other diseases of the digestive system[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes2 notes

• T81 — Complications of procedures, not elsewhere classified[Excludes2](via K91.-): “intraoperative and postprocedural complications of specific body system (D78.-, E36.-, E89.-, G97.3-, G97.4, H59.3-, H59.-, H95.2-, H95.3, I97.4-, I97.5, J95, K91.-, L76.-, M96.-, N99.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• DIG024 — Postprocedural or postoperative digestive system complication[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 463 — Artificial Openings for Feeding or Elimination [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 393 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITH MCC[MS-DRG]: “OTHER DIGESTIVE SYSTEM DIAGNOSES WITH MCC (MDC 06)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 394 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITH CC[MS-DRG]: “OTHER DIGESTIVE SYSTEM DIAGNOSES WITH CC (MDC 06)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 395 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITHOUT CC/MCC[MS-DRG]: “OTHER DIGESTIVE SYSTEM DIAGNOSES WITHOUT CC/MCC (MDC 06)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 791 — PREMATURITY WITH MAJOR PROBLEMS[MS-DRG]: “PREMATURITY WITH MAJOR PROBLEMS (MDC 15)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS[MS-DRG]: “FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 06 — Diseases and Disorders of the Digestive System[MDC crossing]: “Diseases and Disorders of the Digestive System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 5,744 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026
• MDC 15 — Newborns and Other Neonates with Conditions Originating in Perinatal Period[MDC crossing]: “Newborns and Other Neonates with Conditions Originating in Perinatal Period — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Inflammation, inflamed, inflammatory (with exudation), ileoanalpouch (internal)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Inflammation, inflamed, inflammatory (with exudation), intestinal pouch[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Pouchitis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (31)

• K91 — Intraoperative and postprocedural complications and disorders of digestive system, not elsewhere classified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K91.0 — Vomiting following gastrointestinal surgery[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K91.1 — Postgastric surgery syndromes[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K91.2 — Postsurgical malabsorption, not elsewhere classified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K91.3 — Postprocedural intestinal obstruction[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K91.30 — Postprocedural intestinal obstruction, unspecified as to partial versus complete[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K91.31 — Postprocedural partial intestinal obstruction[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• K91.32 — Postprocedural complete intestinal obstruction[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 23 more

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Coding guidelines Official source data

ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Risk adjustment Official source data

2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to K91.850 in its code family, with their registry titles.

• K91.83 — Postprocedural hepatorenal syndrome
• K91.84 — Postprocedural hemorrhage of a digestive system organ or structure following a procedure
• K91.840 — Postprocedural hemorrhage of a digestive system organ or structure following a digestive system procedure
• K91.841 — Postprocedural hemorrhage of a digestive system organ or structure following other procedure
• K91.85 — Complications of intestinal pouch
• K91.858 — Other complications of intestinal pouch
• K91.86 — Retained cholelithiasis following cholecystectomy
• K91.87 — Postprocedural hematoma and seroma of a digestive system organ or structure following a procedure
• K91.870 — Postprocedural hematoma of a digestive system organ or structure following a digestive system procedure
• K91.871 — Postprocedural hematoma of a digestive system organ or structure following other procedure

View all codes in the K91 family