ICD-10-CM 2027
ICD-10 code for Erythroblastosis
From the official ICD-10-CM alphabetic index entry “Erythroblastosis (fetalis) (newborn)”. Page updated September 29, 2026.
About coding Erythroblastosis
The ICD-10-CM code for Erythroblastosis is P55.9 (Hemolytic disease of newborn, unspecified). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on P55.9.
Within P55, choose P55.9 (unspecified) only when documentation doesn't support a more specific option: Rh isoimmunization of newborn (P55.0), ABO isoimmunization of newborn (P55.1) and other hemolytic diseases of newborn (P55.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific Erythroblastosis codes (official index)
Common questions about Erythroblastosis ICD-10 codes
What is the ICD-10 code for Erythroblastosis?
- P55.9 — Hemolytic disease of newborn, unspecified. More specific codes apply when the documentation supports them: P55.1, P55.0.
Is P55.9 billable?
- Yes. P55.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can P55.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict P55.9 as a principal diagnosis.
Is P55.9 a CC or MCC?
- No. P55.9 is neither a CC nor an MCC under MS-DRG v44.0.