P57.9
BillableKernicterus, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is P57.9 an HCC code?
Yes. P57.9 maps to Cerebral Palsy, Except Quadriplegic 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 P57.9
For P57.9 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 P57.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
P57.9 is the ICD-10-CM diagnosis code for kernicterus, unspecified. Brain damage in newborns caused by high levels of bilirubin, but the underlying cause is not specified. P57.9 sits in the ICD-10-CM chapter for certain conditions originating in the perinatal period (p00-p96), within the section covering hemorrhagic and hematological disorders of newborn (p50-p61).
Under the CMS-HCC V28 risk adjustment model, P57.9 maps to Cerebral Palsy, Except Quadriplegic (HCC 192) with a community, non-dual, aged base RAF weight of 0.368. P57.9 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.
Use this code only when the cause of kernicterus cannot be determined; attempt to identify the underlying hemolytic disease or other cause. Because P57.9 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 P57.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the cause of kernicterus cannot be determined; attempt to identify the underlying hemolytic disease or other cause
- •Kernicterus is a reportable condition in many jurisdictions; verify reporting requirements in your facility
Clinical Significance
Kernicterus represents severe bilirubin-induced brain damage that can result in permanent neurological sequelae including cerebral palsy, hearing loss, and developmental delays. This condition requires immediate recognition and management to prevent long-term complications and represents a high-risk neonatal condition for risk adjustment purposes.
Documentation Requirements
- ✓Evidence of elevated bilirubin levels (total and unconjugated)
- ✓Clinical signs of bilirubin encephalopathy or brain damage
- ✓Neurological examination findings consistent with kernicterus
- ✓Age at diagnosis and gestational age at birth
- ✓Associated risk factors (prematurity, blood type incompatibility)
- ✓Treatment interventions (phototherapy, exchange transfusion)
- ✓Imaging studies if performed (MRI, CT)
- ✓Long-term follow-up plans for developmental assessment