2026 ICD-10-CM Diagnosis Code P74.21Hypernatremia of newborn

ICD-10-CM Codes›P00–P96›P70-P74›P74

ICD-10-CM P74.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

P74.21 is a billable ICD-10-CM diagnosis code for hypernatremia of newborn. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as disturbances of sodium balance of newborn. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified perinatal conditions.

Code Identity

ICD-10-CM Code
P74.21
Billable Status
Yes — Valid for Submission
Code Describes
Hypernatremia of newborn
Short Description
Hypernatremia of newborn
Same as the full description in the CMS dataset.
Parent Code
P74.2
Disturbances of sodium balance of newborn

Code Classification

ChapterP00–P96Certain conditions originating in the perinatal period
SectionP70-P74Transitory endocrine and metabolic disorders specific to newborn
CategoryP74Other transitory neonatal electrolyte and metabolic disturbances
This CodeP74.21Hypernatremia of newborn

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disturbances of sodium balance of newborn
  • Hypernatremia
  • Transitory neonatal electrolyte disturbance
  • Transitory neonatal hypernatremia

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disturbance(s)
      • electrolyte
        • newborn, transitory
          • sodium balance
            • hypernatremia
    • Disturbance(s)
      • sodium balance, newborn
        • hypernatremia
    • Imbalance
      • electrolyte
        • neonatal, transitory NEC
          • sodium
            • hypernatremia
    • Newborn(infant) (liveborn) (singleton)
      • hypernatremia

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR PNL013
Other specified and unspecified perinatal conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Hypernatremia

    excessive amount of sodium in the blood. (dorland, 27th ed)

  • Grade 1 Hypernatremia, CTCAE|Grade 1 Hypernatremia

    >uln - 150 mmol/l

  • Grade 2 Hypernatremia, CTCAE|Grade 2 Hypernatremia

    >150 - 155 mmol/l; intervention initiated

  • Grade 3 Hypernatremia, CTCAE|Grade 3 Hypernatremia

    >155 - 160 mmol/l; hospitalization indicated

  • Grade 1 Hypernatremia, CTCAE|Grade 1 Hypernatremia

    >uln-150 mmol/l

  • Grade 2 Hypernatremia, CTCAE|Grade 2 Hypernatremia

    >150-155 mmol/l; intervention initiated

  • Grade 3 Hypernatremia, CTCAE|Grade 3 Hypernatremia

    >155-160 mmol/l; hospitalization indicated

  • Grade 4 Hypernatremia, CTCAE|Grade 4 Hypernatremia

    >160 mmol/l; life-threatening consequences

  • Grade 5 Hypernatremia, CTCAE|Grade 5 Hypernatremia

    death

  • Hypernatremia

    higher than normal levels of sodium in the circulating blood.

  • Hypernatremia, CTCAE|Hypernatremia|Hypernatremia

    a disorder characterized by laboratory test results that indicate an elevation in the concentration of sodium in the blood.

Patient EducationClinical

Fluid and Electrolyte Balance

Electrolytes are minerals that have an electric charge when they are dissolved in water or body fluids, including blood. The electric charge can be positive or negative. You have electrolytes in your blood, urine (pee), tissues, and other body fluids.

The full article covers:

  • What are electrolytes?
  • What are the different types of electrolytes in your body?
  • What is an electrolyte imbalance?
  • What are the different types of electrolyte imbalances?
  • How are electrolyte imbalances diagnosed?
  • What are the treatments for electrolyte imbalances?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code History & ChangesHistory

Replacement P74.21 replaces the following previously assigned code(s):

  • P74.2 - Disturbances of sodium balance of newborn
FY 2019AddedAdded to the ICD-10-CM code setEffective October 1, 2018.
FY 2020–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About P74.21Overview

Is P74.21 (Disturbances of sodium balance of newborn) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report hypernatremia of newborn on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.