R65.21
BillableSevere sepsis with septic shock
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is R65.21 an HCC code?
Yes. R65.21 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 R65.21
For R65.21 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 R65.21 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
R65.21 is the ICD-10-CM diagnosis code for severe sepsis with septic shock. A life-threatening condition where a serious infection has caused severe inflammation and the patient's blood pressure has dropped dangerously low despite treatment. R65.21 sits in the ICD-10-CM chapter for symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (r00-r99), within the section covering general symptoms and signs (r50-r69).
Under the CMS-HCC V28 risk adjustment model, R65.21 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 R65.21 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.
This is a medical emergency; code the specific infection source and causative organism. Because R65.21 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 R65.21 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a medical emergency; code the specific infection source and causative organism
- •Document vasopressor use and organ dysfunction to support the septic shock diagnosis
Clinical Significance
Severe sepsis with septic shock represents the most critical form of sepsis where systemic infection has progressed to multi-organ dysfunction with cardiovascular collapse despite adequate fluid resuscitation. This diagnosis carries extremely high mortality rates and requires immediate intensive care management with vasopressors, broad-spectrum antibiotics, and aggressive supportive care.
Documentation Requirements
- ✓Documentation of sepsis or severe sepsis as the underlying condition
- ✓Evidence of shock (hypotension, need for vasopressors, or organ hypoperfusion)
- ✓Documentation that shock persists despite adequate fluid resuscitation
- ✓Identification of infectious source or suspected infection
- ✓Laboratory evidence supporting sepsis (elevated lactate, procalcitonin, or other biomarkers)
- ✓Evidence of organ dysfunction (acute kidney injury, respiratory failure, altered mental status)
- ✓Documentation of systemic inflammatory response syndrome (SIRS) criteria
- ✓Treatment with vasopressors or inotropic agents
Excludes 1 — Do NOT code together
- postprocedural septic shock (T81.12-)