A48.3
BillableToxic shock syndrome
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A48.3 an HCC code?
Yes. A48.3 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 A48.3
For A48.3 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 A48.3 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
A48.3 is the ICD-10-CM diagnosis code for toxic shock syndrome. Toxic shock syndrome is a rare but serious condition caused by bacterial toxins that enter the bloodstream, leading to a sudden drop in blood pressure, high fever, and potential organ failure. It can develop rapidly and requires immediate medical treatment. A48.3 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, A48.3 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 A48.3 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.
Always verify the causative organism (Staphylococcus aureus or Streptococcus pyogenes) in the medical record and code additional organism codes if documented. Because A48.3 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 A48.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always verify the causative organism (Staphylococcus aureus or Streptococcus pyogenes) in the medical record and code additional organism codes if documented
- •Ensure you capture any associated complications such as acute kidney injury, sepsis, or organ dysfunction with additional ICD-10-CM codes, as toxic shock syndrome often presents with multi-system involvement
Clinical Significance
Toxic shock syndrome is a high-acuity, life-threatening condition that maps to one of the highest-weighted HCCs in risk adjustment. Accurate capture is critical because it reflects significant acute illness burden and resource utilization. This diagnosis demands immediate clinical intervention and carries substantial mortality risk.
Documentation Requirements
- ✓Identification of causative organism (Staphylococcus aureus or Streptococcus pyogenes) with culture results
- ✓Clinical criteria met: fever >=102F, hypotension (systolic BP <=90 mmHg), diffuse macular rash with desquamation
- ✓Multi-organ involvement documented (e.g., renal, hepatic, hematologic, CNS dysfunction)
- ✓Source of infection (wound, tampon use, surgical site, post-partum)
- ✓Severity indicators: vasopressor requirements, ICU admission, mechanical ventilation