P91.61
BillableMild hypoxic ischemic encephalopathy [HIE]
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is P91.61 an HCC code?
Yes. P91.61 maps to Coma, Brain Compression/Anoxic Damage under the CMS-HCC V28 risk adjustment model.
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 P91.61
For P91.61 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 P91.61 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
P91.61 is the ICD-10-CM diagnosis code for mild hypoxic ischemic encephalopathy [hie]. A newborn's mild brain injury from insufficient oxygen and blood flow during birth or pregnancy, with minimal neurological effects. P91.61 sits in the ICD-10-CM chapter for certain conditions originating in the perinatal period (p00-p96), within the section covering other disorders originating in the perinatal period (p90-p96).
Under the CMS-HCC V28 risk adjustment model, P91.61 maps to Coma, Brain Compression/Anoxic Damage (HCC 202) with a community, non-dual, aged base RAF weight of 0.000. P91.61 was not retained as a payment HCC under the older V24 model, so V28 introduced or recategorized it during the 2024–2026 phase-in. 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.
Document the clinical findings supporting 'mild' severity, such as minimal seizures or brief altered consciousness. Because P91.61 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 P91.61 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the clinical findings supporting 'mild' severity, such as minimal seizures or brief altered consciousness
- •Ensure documentation clearly distinguishes mild HIE from moderate or severe presentations to support accurate code selection
Clinical Significance
Mild HIE represents the least severe form of perinatal brain injury from oxygen deprivation, but still carries risk for subtle neurological deficits. This diagnosis requires ongoing neurodevelopmental monitoring and may benefit from early intervention services to optimize outcomes.
Documentation Requirements
- ✓Specific documentation of mild severity HIE
- ✓Evidence of perinatal hypoxic-ischemic event with minimal symptoms
- ✓Mild clinical signs (minimal alteration in consciousness, normal tone)
- ✓Sarnat staging criteria supporting mild classification
- ✓Neuroimaging findings minimal or absent
- ✓EEG typically normal or mildly abnormal
- ✓Response to conservative management
- ✓Normal or near-normal neurological examination