A22.7
BillableAnthrax sepsis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A22.7 an HCC code?
Yes. A22.7 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).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.
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.
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 0.455. The V24 model used during the PY2024–PY2025 transition mapped A22.7 the same way and at the same RAF weight. 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