A22.7 ICD-10-CM Code: Anthrax sepsis
A22.7 maps to CMS-HCC V28 2 (RAF 0.500). Documentation must support MEAT. MEAT criteria · RAF calculator · free HCC coding tools
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Certain zoonotic bacterial diseases (A20-A28)
A22.7
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAnthrax sepsis
Anthrax sepsis is a severe, life-threatening bloodstream infection caused by the bacterium Bacillus anthracis that has spread throughout the body. This condition requires immediate medical treatment and is often fatal if not treated promptly with antibiotics.
Buddy Insight
Anthrax sepsis represents systemic Bacillus anthracis infection in the bloodstream, carrying extremely high mortality.
CMS-HCC V28
MappedHCC 2
RAF 0.500
CMS-HCC V24
MappedHCC 2
RAF 0.352
ACA/HHS
MappedHCC 2
Varies by metal level
ESRD/PACE
MappedHCC 2
RAF 0.087
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for A22.7 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A22.7 in this effective period.
Related Child Codes
Includes
Official- infection due to Bacillus anthracis
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A22.7 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A22.7 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A22.7 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A22.7 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is A22.7 an HCC code?
Yes. A22.7 (Anthrax sepsis) maps to Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock under the CMS-HCC V28 risk adjustment model (and Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock under V24), with a community non-dual aged RAF of 0.500. It is billable for payment year 2026.
Coder answer: A22.7 is billable and maps to V28 HCC 2, Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- A22.7
- Description
- Anthrax sepsis
- HCC (V28)
- HCC 2 — Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock
- RAF
- 0.500
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
Work A22.7 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for A22.7
For A22.7 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed A22.7 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
A22.7 is the ICD-10-CM diagnosis code for anthrax sepsis. Anthrax sepsis is a severe, life-threatening bloodstream infection caused by the bacterium Bacillus anthracis that has spread throughout the body. This condition requires immediate medical treatment and is often fatal if not treated promptly with antibiotics. A22.7 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering certain zoonotic bacterial diseases (a20-a28).
Under the CMS-HCC V28 risk adjustment model, A22.7 maps to Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock (HCC 2) with a community, non-dual, aged base RAF weight of 0.500. Under the older V24 model, A22.7 mapped to the same category but with a base RAF weight of 0.352, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Anthrax sepsis is a reportable condition in most jurisdictions; verify local public health reporting requirements when coding this diagnosis. Because A22.7 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A22.7 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Anthrax sepsis is a reportable condition in most jurisdictions; verify local public health reporting requirements when coding this diagnosis
- •Ensure the clinical documentation clearly indicates sepsis (systemic inflammatory response) rather than localized anthrax infection; code A22.7 specifically for the septic form
Clinical Significance
Anthrax sepsis represents systemic Bacillus anthracis infection in the bloodstream, carrying extremely high mortality. It typically develops as a complication of inhalational or gastrointestinal anthrax and is a medical emergency requiring combination antibiotic therapy, antitoxin treatment, and intensive care support.
Documentation Requirements
- ✓Blood cultures positive for Bacillus anthracis or clinical sepsis in confirmed anthrax case
- ✓Documentation of systemic inflammatory response and hemodynamic compromise
- ✓Organ dysfunction assessment (multi-organ failure is common)
- ✓Primary anthrax form identified (inhalational, cutaneous, gastrointestinal) if applicable
- ✓Anthrax antitoxin administration documentation
Commonly Confused Codes
- •A22.1 (Pulmonary anthrax): A22.1 is pulmonary infection; A22.7 is bloodstream infection: code both when sepsis complicates pulmonary anthrax
- •A41.9 (Sepsis, unspecified): Use A22.7 when anthrax is the identified sepsis organism
- •A22.9 (Anthrax, unspecified): Use A22.7 specifically when sepsis/septicemia is documented, not the unspecified code