2026 ICD-10-CM Diagnosis Code P81.8Other specified disturbances of temperature regulation of newborn

ICD-10-CM Codes›P00–P96›P80-P83›P81

ICD-10-CM P81.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

P81.8 is a billable ICD-10-CM diagnosis code for other specified disturbances of temperature regulation 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 biphasic fever. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified perinatal conditions.

Code Identity

ICD-10-CM Code
P81.8
Billable Status
Yes — Valid for Submission
Code Describes
Other specified disturbances of temperature regulation of newborn
Short Description
Oth disturbances of temperature regulation of newborn
Parent Code
P81
Other disturbances of temperature regulation of newborn

Code Classification

ChapterP00–P96Certain conditions originating in the perinatal period
SectionP80-P83Conditions involving the integument and temperature regulation of newborn
CategoryP81Other disturbances of temperature regulation of newborn
This CodeP81.8Other specified disturbances of temperature regulation of newborn

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Biphasic fever
  • Dehydration fever in newborn
  • Fever of newborn
  • Neonatal dehydration
  • Swinging fever
  • Transitory fever of newborn

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.

    • Disorder(of)
      • temperature regulation, newborn
        • specified NEC
    • Disturbance(s)
      • temperature
        • regulation, newborn
          • specified NEC

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

Uncommon Infant and Newborn Problems

It can be scary when your baby is sick, especially when it is not an everyday problem like a cold or a fever. You may not know whether the problem is serious or how to treat it. If you have concerns about your baby's health, call your health care provider right away.

Read the full article at MedlinePlus

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

Convert P81.8 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
778.4 NB temp regulat dis NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About P81.8Overview

Is P81.8 (Other disturbances of temperature regulation of newborn) a billable code?

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

What is the ICD-9 equivalent of P81.8?

Under the General Equivalence Mappings, other specified disturbances of temperature regulation of newborn converts to ICD-9-CM 778.4 (NB temp regulat dis NEC). The mapping is approximate, so confirm the match fits the documentation.

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.