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A09 ICD-10-CM Code: Infectious gastroenteritis and colitis, unspecified

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Official description

A09

Infectious gastroenteritis and colitis, unspecified

ICD-10-CM diagnosis code · United States clinical modification

Where A09 sits

  1. 1

    Chapter 1

    Certain infectious and parasitic diseases (A00-B99)

  2. 2

    Section

    Intestinal infectious diseases (A00-A09)

  3. 3

    Category A09

    Infectious gastroenteritis and colitis, unspecified

  4. 4

    Code A09

    Infectious gastroenteritis and colitis, unspecified

Notes for this code

Inclusion terms

  • Infectious colitis NOS
  • Infectious enteritis NOS
  • Infectious gastroenteritis NOS

Code first

No “code first” instruction is listed for A09.

Use additional code

No “use additional code” instruction is listed for A09.

Excludes1

Conditions that should not be reported together with this code.

  • colitis NOS (K52.9)
  • diarrhea NOS (R19.7)
  • enteritis NOS (K52.9)
  • gastroenteritis NOS (K52.9)
  • noninfective gastroenteritis and colitis, unspecified (K52.9)

Excludes2

Conditions not included here that may be reported separately when present.

No Excludes2 note is listed for A09.

Source and release

Data release
U.S. ICD-10-CM · FY 2027
Effective date
Oct 1, 2026

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Frequently asked questions

What does ICD-10-CM code A09 mean?

A09 is the FY 2027 U.S. ICD-10-CM code for “Infectious gastroenteritis and colitis, unspecified.”

Is A09 a billable or specific ICD-10-CM code?

Yes. In the FY 2027 reference data used on this page, A09 has no child codes and is presented as a billable/specific code. Always confirm the active code set and payer requirements before use.

Where is A09 located in ICD-10-CM?

A09 is listed in Chapter 1, Certain infectious and parasitic diseases (A00-B99), within Intestinal infectious diseases (A00-A09) (A00–A09), under category A09, Infectious gastroenteritis and colitis, unspecified.

What coding notes are listed for A09?

Its listed inclusion terms are Infectious colitis NOS; Infectious enteritis NOS; Infectious gastroenteritis NOS. No code-first instruction is listed. Excludes1 notes: colitis NOS (K52.9); diarrhea NOS (R19.7); enteritis NOS (K52.9); gastroenteritis NOS (K52.9); noninfective gastroenteritis and colitis, unspecified (K52.9). No Excludes2 note is listed.