2026 ICD-10-CM Diagnosis Code P35.9Congenital viral disease, unspecified

ICD-10-CM Codes›P00–P96›P35-P39›P35

ICD-10-CM P35.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

P35.9 is a billable ICD-10-CM diagnosis code for congenital viral disease, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as acquired neutropenia. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Perinatal infections and Viral infection.

Code Identity

ICD-10-CM Code
P35.9
Billable Status
Yes — Valid for Submission
Code Describes
Congenital viral disease, unspecified
Short Description
Congenital viral disease, unspecified
Same as the full description in the CMS dataset.
Parent Code
P35
Congenital viral diseases

Code Classification

ChapterP00–P96Certain conditions originating in the perinatal period
SectionP35-P39Infections specific to the perinatal period
CategoryP35Congenital viral diseases
This CodeP35.9Congenital viral disease, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acquired neutropenia
  • Acquired neutropenia in newborn
  • Congenital viral disease
  • Transient neonatal neutropenia
  • Transient neonatal neutropenia due to congenital viral infection

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.

    • Disease, diseased
      • infectious, infective
        • congenital
          • viral
    • Disease, diseased
      • viral, virus
        • congenital
    • Infection, infected, infective(opportunistic)
      • congenital
        • virus

Clinical ClassificationClinical

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

CCSR PNL009
Perinatal infections
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INF008
Viral infection
Default principal diagnosis: inpatient No · outpatient No

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 P35.9 to ICD-9-CMHistory

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

ICD-9-CM
771.2 Congenital infec 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 P35.9Overview

Is P35.9 (Congenital viral diseases) a billable code?

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

What is the ICD-9 equivalent of P35.9?

Under the General Equivalence Mappings, congenital viral disease, unspecified converts to ICD-9-CM 771.2 (congenital infec 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.