2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

P74.21 is a billable ICD-10-CM diagnosis code for hypernatremia of newborn. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 791, 793. Coders also document this condition as disturbance 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.

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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to P74.21: its own notes plus those printed at block P70-P74 and Chapter 16. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Block P70-P74 Transitory endocrine and metabolic disorders specific to newborn applies to 33 codes
  • transitory endocrine and metabolic disturbances caused by the infant's response to maternal endocrine and metabolic factors, or its adjustment to extrauterine environment
From Chapter 16 (P00-P96) Certain conditions originating in the perinatal period applies to 463 codes
  • conditions that have their origin in the fetal or perinatal period (before birth through the first 28 days after birth) even if morbidity occurs later

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 16 (P00-P96) Certain conditions originating in the perinatal period applies to 463 codes
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • tetanus neonatorum (A33)

Notes

General instructions on how these codes are used.

From Chapter 16 (P00-P96) Certain conditions originating in the perinatal period applies to 463 codes
  • Codes from this chapter are for use on newborn records only, never on maternal records

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name P74.21, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming P74.21: they are not reported together with it, unless the two conditions are unrelated.

  • Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases
    transitory endocrine and metabolic disorders specific to newborn (P70-P74) names P70-P74, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming P74.21: its condition is not part of those codes, and both may be reported when the patient has both.

  • P00 Newborn affected by maternal conditions that may be unrelated to present pregnancy
    newborn affected by maternal endocrine and metabolic disorders (P70-P74) names P70-P74, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

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 2020–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About P74.21Overview

What is the ICD-10 code for hypernatremia of newborn?

The ICD-10-CM code for hypernatremia of newborn is P74.21 (sometimes written as P7421). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

What MS-DRG does P74.21 group to?

When hypernatremia of newborn is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, with relative weights from 4.1073 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.