ICD-10-CM 2027
ICD-10 code for anthrax
From the official ICD-10-CM alphabetic index entry “Anthrax”. Page updated September 29, 2026.
About coding anthrax
The ICD-10-CM code for anthrax is A22.9 (Anthrax, unspecified). The official index lists 12 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on A22.9.
Within A22, choose A22.9 (unspecified) only when documentation doesn't support a more specific option: cutaneous anthrax (A22.0), pulmonary anthrax (A22.1), gastrointestinal anthrax (A22.2), sepsis (A22.7) and other forms of anthrax (A22.8).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 867 (Other Infectious and Parasitic Diseases Diagnoses with MCC, relative weight 2.1859), DRG 868 (Other Infectious and Parasitic Diseases Diagnoses with CC, relative weight 1.0235) and DRG 869 (Other Infectious and Parasitic Diseases Diagnoses without CC/MCC, relative weight 0.6787), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), 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 anthrax codes (official index)
- with pneumonia A22.1 — Pulmonary anthrax
- cerebral A22.8 — Other forms of anthrax
- colitis A22.2 — Gastrointestinal anthrax
- cutaneous A22.0 — Cutaneous anthrax
- gastrointestinal A22.2 — Gastrointestinal anthrax
- inhalation A22.1 — Pulmonary anthrax
- intestinal A22.2 — Gastrointestinal anthrax
- meningitis A22.8 — Other forms of anthrax
- pulmonary A22.1 — Pulmonary anthrax
- respiratory A22.1 — Pulmonary anthrax
- sepsis A22.7 — Anthrax sepsis
- specified manifestation NEC A22.8 — Other forms of anthrax
Common questions about anthrax ICD-10 codes
What is the ICD-10 code for anthrax?
- A22.9 — Anthrax, unspecified. More specific codes apply when the documentation supports them: A22.1, A22.8, A22.2, A22.0 and others below.
What is the ICD-10 code for cerebral anthrax?
- A22.8 — Other forms of anthrax.
What is the ICD-10 code for colitis anthrax?
- A22.2 — Gastrointestinal anthrax.
What is the ICD-10 code for cutaneous anthrax?
- A22.0 — Cutaneous anthrax.
What is the ICD-10 code for gastrointestinal anthrax?
- A22.2 — Gastrointestinal anthrax.
What is the ICD-10 code for inhalation anthrax?
- A22.1 — Pulmonary anthrax.
What is the ICD-10 code for intestinal anthrax?
- A22.2 — Gastrointestinal anthrax.
Is A22.9 billable?
- Yes. A22.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can A22.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict A22.9 as a principal diagnosis.
Is A22.9 a CC or MCC?
- A22.9 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.