P36.5
BillableSepsis of newborn due to anaerobes
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is P36.5 an HCC code?
Yes. P36.5 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 P36.5
For P36.5 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 P36.5 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
P36.5 is the ICD-10-CM diagnosis code for sepsis of newborn due to anaerobes. A serious blood infection in a newborn caused by anaerobic bacteria (bacteria that grow without oxygen). P36.5 sits in the ICD-10-CM chapter for certain conditions originating in the perinatal period (p00-p96), within the section covering infections specific to the perinatal period (p35-p39).
Under the CMS-HCC V28 risk adjustment model, P36.5 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 P36.5 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.
Anaerobic sepsis in newborns is less common; ensure anaerobic culture results are documented and reviewed. Because P36.5 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 P36.5 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Anaerobic sepsis in newborns is less common; ensure anaerobic culture results are documented and reviewed
- •Identify the specific anaerobic organism if possible for more precise coding
Clinical Significance
Anaerobic sepsis in newborns is a serious infection caused by bacteria that grow without oxygen, often associated with maternal chorioamnionitis, prolonged rupture of membranes, or gastrointestinal sources. These infections can be particularly challenging to diagnose and treat due to special culture requirements and potential for mixed bacterial infections.
Documentation Requirements
- ✓Positive anaerobic culture results
- ✓Clinical signs of sepsis syndrome
- ✓Associated maternal risk factors
- ✓Anaerobic culture techniques utilized
- ✓Antibiotic coverage for anaerobic organisms
- ✓Gestational age and birth weight
- ✓Source of infection if identified
- ✓Treatment response and duration