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K81.0 ICD-10-CM Code: Acute cholecystitis

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
7 inclusion terms · 1 Excludes1 · 1 use-additional code

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 444 — DISORDERS OF THE BILIARY TRACT WITH MCC (MDC 07)
  • MS-DRG 445 — DISORDERS OF THE BILIARY TRACT WITH CC (MDC 07)
  • MS-DRG 446 — DISORDERS OF THE BILIARY TRACT WITHOUT CC/MCC (MDC 07)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for K81.0 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 K81.0 itself; “inherited from” names the category or block whose note applies here.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Abscess of gallbladder
  • Angiocholecystitis
  • Emphysematous (acute) cholecystitis
  • Empyema of gallbladder
  • Gangrene of gallbladder
  • Gangrenous cholecystitis
  • Suppurative cholecystitis

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Source: inherited from K81

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code if applicable for associated gangrene of gallbladder (K82.A1), or perforation of gallbladder (K82.A2)

Source: inherited from K81

Coder workflow for K81.0

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

Before you code K81.0

  1. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with K81.0. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in K81.0’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewK80

Consider K81.0. Then work the Use Additional Code note, and confirm the code is valid for the date of service in the Verify section.

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).
Acuity
Acute or chronic as documented; when both are documented and separate codes exist, both are reported with the acute code first (Guidelines I.B.8).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

  • Excludes1 — check before selecting K81.0(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with K81.0: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareK80

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

  • Use Additional Code — after identifying K81.0(1 note)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with K81.0 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewK82.A1, K82.A2

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition K81.0 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewK80

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with K81.0?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewK82.A1, K82.A2

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.

Code Overview

Acute cholecystitis is a billable ICD-10-CM diagnosis code (K81.0).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (6)

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.

Official Coding Guidelines

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

Chapter 11: Diseases of the Digestive System (K00-K95)

Reserved for future guideline expansion

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 K81.0 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 Excludes1 note: K82.4 — Cholesterolosis of gallbladder (via K81.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Excludes2 note: K83 — Other diseases of biliary tract (via K81.-).

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

Referenced by 1 Code First instruction: K82.A — Disorders of gallbladder in diseases classified elsewhere (via K81.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

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 14 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 444 (MDC 07), DRG 445 (MDC 07), DRG 446 (MDC 07).

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

Clinical classification (AHRQ CCSR):DIG017 — Biliary tract disease (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.

K80.00 — Calculus of gallbladder with acute cholecystitis without obstruction, K80.12 — Calculus of gallbladder with acute and chronic cholecystitis without obstruction, K80.62 — Calculus of gallbladder and bile duct with acute cholecystitis without obstruction, K80.63 — Calculus of gallbladder and bile duct with acute cholecystitis with obstruction, K80.66 — Calculus of gallbladder and bile duct with acute and chronic cholecystitis without obstruction, K80.67 — Calculus of gallbladder and bile duct with acute and chronic cholecystitis with obstruction, K81.1 — Chronic cholecystitis, K81.2 — Acute cholecystitis with chronic cholecystitis, K81.9 — Cholecystitis, unspecified, K82.9 — Disease of gallbladder, unspecified, K83.5 — Biliary cyst, K83.8 — Other specified diseases of biliary tract, K83.9 — Disease of biliary tract, unspecified

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Biliary tract disease).

K80.62 — Calculus of gallbladder and bile duct with acute cholecystitis without obstruction, K80.63 — Calculus of gallbladder and bile duct with acute cholecystitis with obstruction, K80.64 — Calculus of gallbladder and bile duct with chronic cholecystitis without obstruction, K80.65 — Calculus of gallbladder and bile duct with chronic cholecystitis with obstruction, K80.66 — Calculus of gallbladder and bile duct with acute and chronic cholecystitis without obstruction, K80.67 — Calculus of gallbladder and bile duct with acute and chronic cholecystitis with obstruction, K80.70 — Calculus of gallbladder and bile duct without cholecystitis without obstruction, K80.71 — Calculus of gallbladder and bile duct without cholecystitis with obstruction, K80.80 — Other cholelithiasis without obstruction, K80.81 — Other cholelithiasis with obstruction, K81.1 — Chronic cholecystitis, K81.2 — Acute cholecystitis with chronic cholecystitis, K81.9 — Cholecystitis, unspecified, K82.0 — Obstruction of gallbladder, K82.1 — Hydrops of gallbladder, K82.2 — Perforation of gallbladder, K82.3 — Fistula of gallbladder, K82.4 — Cholesterolosis of gallbladder, K82.8 — Other specified diseases of gallbladder, K82.9 — Disease of gallbladder, unspecified, +45 more

Same Index main term, other category

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

K65.0 — Generalized (acute) peritonitis (pelvis, pelvic, male), K65.1 — Peritoneal abscess (omentum), K68.11 — Postprocedural retroperitoneal abscess (postoperative, retroperitoneal), K68.12 — Psoas muscle abscess (psoas muscle), K68.19 — Other retroperitoneal abscess (presacral), K6A.01 — Prevesical abscess (retropubic), K6A.09 — Other pelvic abscess (pelvis, pelvic), K75.0 — Abscess of liver (liver), K80.12 — Calculus of gallbladder with acute and chronic cholecystitis without obstruction (chronic, with acute cholecystitis, with gallbladder calculus), K80.13 — Calculus of gallbladder with acute and chronic cholecystitis with obstruction (chronic, with acute cholecystitis, with gallbladder calculus, with obstruction), K82.A1 — Gangrene of gallbladder in cholecystitis (with, gangrene of gallbladder), K82.A2 — Perforation of gallbladder in cholecystitis (with, perforation of gallbladder), K85.80 — Other acute pancreatitis without necrosis or infection (pancreas, acute), K94.02 — Colostomy infection (colostomy), K94.12 — Enterostomy infection (ileostomy), L02.01 — Cutaneous abscess of face (face), L02.11 — Cutaneous abscess of neck (neck), L02.211 — Cutaneous abscess of abdominal wall (loin), L02.212 — Cutaneous abscess of back [any part, except buttock and flank] (back), L02.213 — Cutaneous abscess of chest wall (pectoral), +175 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Blood Glucose Test, Gamma-glutamyl Transferase (GGT) Test

Contextual Map

Every relationship of K81.0 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 K81.0 with these 3 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Referenced by Code First instructions

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 07 — Diseases and Disorders of the Hepatobiliary System and Pancreas[MDC crossing]: “Diseases and Disorders of the Hepatobiliary System and Pancreas — 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. 2,481 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic), gallbladder[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Cholecystitis, acute (emphysematous) (gangrenous) (suppurative)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Empyema (acute) (chest) (double) (pleura) (supradiaphragmatic) (thorax), gallbladder[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Gallbladder, acute[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Septic, gallbladder (acute)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Suppuration, suppurative, gallbladder (acute)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

Change history

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

Real-World Coding Questions

Questions working coders have asked about this code, answered from official sources and reviewed by an editor.

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
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

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "K81.0 — Acute cholecystitis." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/k81.0-acute-cholecystitis

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Acute cholecystitis

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to K81.0 in its code family, with their registry titles.

View all codes in the K81 family