A42.7
BillableActinomycotic sepsis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A42.7 an HCC code?
Yes. A42.7 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 A42.7
For A42.7 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 A42.7 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
A42.7 is the ICD-10-CM diagnosis code for actinomycotic sepsis. A serious bloodstream infection caused by Actinomyces bacteria, a type of organism that normally lives in the mouth and can cause severe infection if it spreads throughout the body. This is a life-threatening condition requiring immediate medical treatment with antibiotics. A42.7 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other bacterial diseases (a30-a49).
Under the CMS-HCC V28 risk adjustment model, A42.7 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 A42.7 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.
Verify that sepsis is documented in the medical record along with the actinomycotic infection; sepsis requires specific documentation to support this code. Because A42.7 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 A42.7 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify that sepsis is documented in the medical record along with the actinomycotic infection; sepsis requires specific documentation to support this code
- •Check for any associated conditions or complications (such as abscesses, endocarditis, or organ involvement) that may require additional codes
Clinical Significance
Actinomycotic sepsis is a rare but severe bloodstream infection caused by Actinomyces species, indicating advanced disseminated disease. Actinomyces species are fastidious anaerobes that may be missed on routine blood cultures if anaerobic cultures are not held for sufficient time (typically requires 14+ days of incubation).
Documentation Requirements
- ✓Blood cultures positive for Actinomyces species (note: requires prolonged incubation of anaerobic bottles)
- ✓Clinical documentation of sepsis with systemic inflammatory response
- ✓Source of dissemination identified (cervicofacial, thoracic, abdominopelvic, or IUD-associated pelvic actinomycosis)
- ✓Organ dysfunction and severity assessment
- ✓Prolonged antibiotic treatment plan (IV penicillin transitioning to oral, 6-12 months total)