P74.21
BillableHypernatremia of newborn
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is P74.21 an HCC code?
No. P74.21 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
P74.21 is the ICD-10-CM diagnosis code for hypernatremia of newborn. A condition where a newborn has abnormally high levels of sodium in their blood. P74.21 sits in the ICD-10-CM chapter for certain conditions originating in the perinatal period (p00-p96), within the section covering transitory endocrine and metabolic disorders specific to newborn (p70-p74).
P74.21 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Confirm sodium levels from laboratory results; typically defined as serum sodium >150 mEq/L in neonates.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for P74.21 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm sodium levels from laboratory results; typically defined as serum sodium >150 mEq/L in neonates
- •Document the underlying cause such as dehydration, excessive sodium intake, or inadequate free water intake