2027 ICD-10-CM Diagnosis Code K36Other appendicitis

ICD-10-CM Codes›K00–K95›K35-K38›K36

ICD-10-CM K36
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

K36 is a billable ICD-10-CM diagnosis code for other appendicitis. 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. Coders also document this condition as atypical appendicitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Appendicitis and other appendiceal conditions.

Code Identity

ICD-10-CM Code
K36
Billable Status
Yes — Valid for Submission
Code Describes
Other appendicitis
Short Description
Other appendicitis
Same as the full description in the CMS dataset.
Chapter
K35-K38
Diseases of appendix

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK35-K38Diseases of appendix
CategoryK36Other appendicitis
This CodeK36Other appendicitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Atypical appendicitis
  • Catarrhal appendicitis
  • Chronic appendicitis
  • Chronic appendicitis with perforation of appendix
  • Healed appendicitis
  • Pelvic appendicitis
  • Perforation of appendix
  • Recurrent appendicitis
  • Subacute appendicitis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to K36: its own notes plus those printed at Chapter 11. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Chronic appendicitis
  • Recurrent appendicitis

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.

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

Appendicitis

The appendix is a small, tube-like organ attached to the first part of the large intestine. It is located in the lower right part of the abdomen. It has no known function. A blockage inside of the appendix causes appendicitis. The blockage leads to increased pressure, problems with blood flow, and inflammation.

Read the full article at MedlinePlus

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

Convert K36 to ICD-9-CMHistory

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

ICD-9-CM
542 Other appendicitis
Exact Match The mapping is direct, with no qualifiers.

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 K36Overview

What is the ICD-10 code for other appendicitis?

The ICD-10-CM code for other appendicitis is K36. It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is K36 (Other appendicitis) a billable code?

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

What MS-DRG does K36 group to?

When other appendicitis 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 K36?

Under the General Equivalence Mappings, other appendicitis converts to ICD-9-CM 542 (other appendicitis). The mapping is a direct match.