2027 ICD-10-CM Diagnosis Code K38.3Fistula of appendix

ICD-10-CM Codes›K00–K95›K35-K38›K38

ICD-10-CM K38.3
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

K38.3 is a billable ICD-10-CM diagnosis code for fistula of appendix. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 393 through 395. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Appendicitis and other appendiceal conditions.

Code Identity

ICD-10-CM Code
K38.3
Billable Status
Yes — Valid for Submission
Code Describes
Fistula of appendix
Short Description
Fistula of appendix
Same as the full description in the CMS dataset.
Parent Code
K38
Other diseases of appendix

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK35-K38Diseases of appendix
CategoryK38Other diseases of appendix
This CodeK38.3Fistula of appendix

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Fistula of appendix

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to K38.3: its own notes plus those printed at Chapter 11. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 11 (K00-K95) Diseases of the digestive system applies to 863 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name K38.3, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming K38.3: its condition is not part of those codes, and both may be reported when the patient has both.

  • K63.2 Fistula of intestine
    fistula of appendix (K38.3)

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DIG009
Appendicitis and other appendiceal conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Colonic Diseases

Your colon, also known as the large intestine, is part of your digestive system. It's a long, hollow tube at the end of your digestive tract where your body makes and stores stool. Many disorders affect the colon's ability to work properly. Some of these include:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K38.3 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
543.9 Diseases of appendix NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About K38.3Overview

What is the ICD-10 code for fistula of appendix?

The ICD-10-CM code for fistula of appendix is K38.3 (sometimes written as K383). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is K38.3 (Other diseases of appendix) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report fistula of appendix on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does K38.3 group to?

When fistula of appendix is the principal diagnosis on an inpatient stay, it groups to MS-DRG 394, 395, 393, with relative weights from 0.6379 to 1.5877 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K38.3?

Under the General Equivalence Mappings, fistula of appendix converts to ICD-9-CM 543.9 (diseases of appendix NEC). The mapping is approximate, so confirm the match fits the documentation.