A09 is the authoritative medical code for Infectious gastroenteritis and colitis, unspecified. This classification is used in medical billing and clinical recording to specify the clinical criteria for infectious gastroenteritis and colitis, unspecified (ICD-10-CM A09), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Infectious gastroenteritis and colitis, unspecified is a billable ICD-10-CM diagnosis code A09. Inclusion terms: Infectious colitis NOS; Infectious enteritis NOS; Infectious gastroenteritis NOS. Excludes1 (not coded here): colitis NOS K52.9; diarrhea NOS R19.7; enteritis NOS K52.9; gastroenteritis NOS K52.9; noninfective gastroenteritis and colitis, unspecified K52.9.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for A09 in the official ICD-10-CM tabular list.
Inclusion Terms
Alternative terms the tabular list files under this code.
- Infectious colitis NOS
- Infectious enteritis NOS
- Infectious gastroenteritis NOS
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- colitis NOS K52.9
- diarrhea NOS R19.7
- enteritis NOS K52.9
- gastroenteritis NOS K52.9
- noninfective gastroenteritis and colitis, unspecified K52.9
Frequently Asked Questions (FAQ) & Clinical Guidance
What can't be coded together with A09?
Per Excludes1 instructions, A09 must not be reported with: colitis NOS (K52.9); diarrhea NOS (R19.7); enteritis NOS (K52.9); gastroenteritis NOS (K52.9).
What conditions are included under A09?
Infectious gastroenteritis and colitis, unspecified includes: Infectious colitis NOS; Infectious enteritis NOS; Infectious gastroenteritis NOS.
Indexed Clinical Terms (19)
Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.
- Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute), in (due to), enteritis, infectious NEC
- Colitis (acute) (catarrhal) (chronic) (noninfective) (hemorrhagic), regional, infectious
- Diarrhea, diarrheal (disease) (infantile) (inflammatory), dysenteric
- Diarrhea, diarrheal (disease) (infantile) (inflammatory), endemic
- Diarrhea, diarrheal (disease) (infantile) (inflammatory), epidemic
- Diarrhea, diarrheal (disease) (infantile) (inflammatory), infectious
- Disease, diseased, diarrheal, infectious NEC
- Dysentery, dysenteric (catarrhal) (diarrhea) (epidemic) (hemorrhagic) (infectious) (sporadic) (tropical)
- Dysentery, dysenteric (catarrhal) (diarrhea) (epidemic) (hemorrhagic) (infectious) (sporadic) (tropical), arthritis
- Enteritis (acute) (diarrheal) (hemorrhagic) (noninfective), epidemic (infectious)
- Enteritis (acute) (diarrheal) (hemorrhagic) (noninfective), infectious NOS
- Enteritis (acute) (diarrheal) (hemorrhagic) (noninfective), septic
- Enterocolitis, infectious NEC
- Gastroenteritis (acute) (chronic) (noninfectious), epidemic (infectious)
- Gastroenteropathy, infectious
- Ileitis (chronic) (noninfectious), infectious
- Ileocolitis, infectious
- Sigmoiditis, infectious
- Ulcer, ulcerated, ulcerating, ulceration, ulcerative, dysenteric
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures:
ICD Code A05
Other bacterial foodborne intoxications, not elsewhere classified
ICD Code A08
Viral and other specified intestinal infections