ICD-10-CM 2027
ICD-10 code for appendicitis
From the official ICD-10-CM alphabetic index entry “Appendicitis (pneumococcal) (retrocecal)”. Page updated September 29, 2026.
About coding appendicitis
The ICD-10-CM code for appendicitis is K37 (Unspecified appendicitis). The official index lists 49 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on K37.
Don't report K37 together with the conditions in its Excludes1 note: unspecified appendicitis with peritonitis (K35.2-, K35.3-).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 393 (Other Digestive System Diagnoses with MCC, relative weight 1.5881), DRG 394 (Other Digestive System Diagnoses with CC, relative weight 0.9228) and DRG 395 (Other Digestive System Diagnoses without CC/MCC, relative weight 0.6382), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific appendicitis codes (official index)
- with
- gangrene K35.891 — Other acute appendicitis without perforation, with gangrene
- with localized peritonitis K35.31 — Acute appendicitis with localized peritonitis and gangrene, without perforation
- perforation NOS K35.32 — Acute appendicitis with perforation, localized peritonitis, and gangrene, without abscess
- peritoneal abscess K35.33 — Acute appendicitis with perforation, localized peritonitis, and gangrene, with abscess
- peritonitis NEC K35.33 — Acute appendicitis with perforation, localized peritonitis, and gangrene, with abscess
- generalized K35.209 — Acute appendicitis with generalized peritonitis, without abscess, unspecified as to perforation
- with
- abscess K35.219 — Acute appendicitis with generalized peritonitis, with abscess, unspecified as to perforation
- with perforation or rupture K35.211 — Acute appendicitis with generalized peritonitis, with perforation and abscess
- following rupture or perforation of appendix NOS K35.211 — Acute appendicitis with generalized peritonitis, with perforation and abscess
- without perforation or rupture K35.210 — Acute appendicitis with generalized peritonitis, without perforation, with abscess
- perforation or rupture K35.201 — Acute appendicitis with generalized peritonitis, with perforation, without abscess
- following rupture or perforation of appendix NOS K35.201 — Acute appendicitis with generalized peritonitis, with perforation, without abscess
- without rupture or perforation of appendix K35.200 — Acute appendicitis with generalized peritonitis, without perforation or abscess
- localized K35.30 — Acute appendicitis with localized peritonitis, without perforation or gangrene
- with
- gangrene K35.31 — Acute appendicitis with localized peritonitis and gangrene, without perforation
- perforation K35.32 — Acute appendicitis with perforation, localized peritonitis, and gangrene, without abscess
- and abscess K35.33 — Acute appendicitis with perforation, localized peritonitis, and gangrene, with abscess
- rupture (with localized peritonitis) K35.32 — Acute appendicitis with perforation, localized peritonitis, and gangrene, without abscess
- acute (catarrhal) (fulminating) (obstructive) (retrocecal) (suppurative) K35.80 — Unspecified acute appendicitis
- with
- gangrene K35.891 — Other acute appendicitis without perforation, with gangrene
- peritoneal abscess K35.33 — Acute appendicitis with perforation, localized peritonitis, and gangrene, with abscess
- peritonitis NEC K35.33 — Acute appendicitis with perforation, localized peritonitis, and gangrene, with abscess
- generalized K35.209 — Acute appendicitis with generalized peritonitis, without abscess, unspecified as to perforation
- with
- abscess K35.219 — Acute appendicitis with generalized peritonitis, with abscess, unspecified as to perforation
- with perforation or rupture K35.211 — Acute appendicitis with generalized peritonitis, with perforation and abscess
- following rupture or perforation of appendix NOS K35.211 — Acute appendicitis with generalized peritonitis, with perforation and abscess
- without perforation or rupture K35.210 — Acute appendicitis with generalized peritonitis, without perforation, with abscess
- perforation or rupture K35.201 — Acute appendicitis with generalized peritonitis, with perforation, without abscess
- following rupture or perforation of appendix NOS K35.201 — Acute appendicitis with generalized peritonitis, with perforation, without abscess
- without rupture or perforation of appendix K35.200 — Acute appendicitis with generalized peritonitis, without perforation or abscess
- localized K35.30 — Acute appendicitis with localized peritonitis, without perforation or gangrene
- with
- gangrene K35.31 — Acute appendicitis with localized peritonitis and gangrene, without perforation
- perforation K35.32 — Acute appendicitis with perforation, localized peritonitis, and gangrene, without abscess
- and abscess K35.33 — Acute appendicitis with perforation, localized peritonitis, and gangrene, with abscess
- specified NEC K35.890 — Other acute appendicitis without perforation or gangrene
- with gangrene K35.891 — Other acute appendicitis without perforation, with gangrene
- with localized peritonitis K35.31 — Acute appendicitis with localized peritonitis and gangrene, without perforation
- amebic A06.89 — Other amebic infections
- chronic (recurrent) K36 — Other appendicitis
- exacerbation
- gangrenous
- healed (obliterative) K36 — Other appendicitis
- interval K36 — Other appendicitis
- neurogenic K36 — Other appendicitis
- obstructive K36 — Other appendicitis
- recurrent K36 — Other appendicitis
- relapsing K36 — Other appendicitis
- ruptured NOS (with localized peritonitis) K35.32 — Acute appendicitis with perforation, localized peritonitis, and gangrene, without abscess
- subacute (adhesive) K36 — Other appendicitis
- subsiding K36 — Other appendicitis
- suppurative
- tuberculous A18.32 — Tuberculous enteritis
Don't confuse with (Excludes1 for K37)
Common questions about appendicitis ICD-10 codes
What is the ICD-10 code for appendicitis?
- K37 — Unspecified appendicitis. More specific codes apply when the documentation supports them: K35.891, K35.31, K35.32, K35.33 and others below.
What is the ICD-10 code for acute appendicitis?
- K35.80 — Unspecified acute appendicitis.
What is the ICD-10 code for amebic appendicitis?
- A06.89 — Other amebic infections.
What is the ICD-10 code for chronic appendicitis?
- K36 — Other appendicitis.
What is the ICD-10 code for healed appendicitis?
- K36 — Other appendicitis.
What is the ICD-10 code for interval appendicitis?
- K36 — Other appendicitis.
What is the ICD-10 code for neurogenic appendicitis?
- K36 — Other appendicitis.
Is K37 billable?
- Yes. K37 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K37 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K37 as a principal diagnosis.
Is K37 a CC or MCC?
- No. K37 is neither a CC nor an MCC under MS-DRG v44.0.