P74.421Hyperchloremia of newborn

P74.421 is the ICD-10-CM diagnosis code for Hyperchloremia of newborn. It belongs to category P74 (other transitory neonatal electrolyte and metabolic disturbances), block P70-P74 (transitory endocrine and metabolic disorders specific to 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 P74.42 (disturbances of chlorine balance of newborn), P74.421 is specifically for Hyperchloremia of newborn. Related codes cover Hypochloremia of newborn (P74.422).

The conditions in its Excludes2 note aren't part of P74.421, but may be coded alongside it if the patient has both: late metabolic acidosis of the newborn (P74.0).

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 was added in FY2019, effective October 1, 2018.