P55.9Hemolytic disease of newborn, unspecified

P55.9 is the ICD-10-CM diagnosis code for hemolytic disease of newborn, unspecified. It belongs to category P55 (hemolytic disease of newborn), block P50-P61 (hemorrhagic and hematological disorders of newborn) and chapter 16 (certain conditions originating in the perinatal period). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

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.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 773.2 (hemolytic disease of fetus or newborn due to other and unspecified isoimmunization).