P55.8
BillableOther hemolytic diseases of newborn
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is P55.8 an HCC code?
Yes. P55.8 maps to Hemolytic and Aplastic Anemias 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 P55.8
For P55.8 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 P55.8 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
P55.8 is the ICD-10-CM diagnosis code for other hemolytic diseases of newborn. Destruction of the newborn's red blood cells due to blood type incompatibility or other immune causes not specified as Rh or ABO. P55.8 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, P55.8 maps to Hemolytic and Aplastic Anemias (HCC 109) with a community, non-dual, aged base RAF weight of 0.291. P55.8 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 for other blood group incompatibilities (Kell, Duffy, Kidd, etc.). Because P55.8 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 P55.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code for other blood group incompatibilities (Kell, Duffy, Kidd, etc.)
- •Document the specific blood group incompatibility identified in testing
Clinical Significance
Other hemolytic diseases in newborns encompass various immune-mediated red blood cell destruction not due to ABO or Rh incompatibility, requiring prompt recognition and treatment to prevent severe anemia and kernicterus. These conditions often require specialized blood banking support and intensive monitoring.
Documentation Requirements
- ✓Evidence of hemolysis not due to ABO or Rh incompatibility
- ✓Documentation of specific blood group antibodies involved
- ✓Laboratory findings showing anemia and elevated bilirubin
- ✓Maternal antibody screening and identification
- ✓Direct and indirect Coombs test results
- ✓Assessment of hemolysis severity and complications
- ✓Treatment plan including phototherapy or exchange transfusion
- ✓Blood bank consultation and compatible blood product identification