2026 ICD-10-CM Diagnosis Code O86.4Pyrexia of unknown origin following delivery

ICD-10-CM Codes›O00-O9A›O85-O92›O86

ICD-10-CM O86.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O86.4 is a billable ICD-10-CM diagnosis code for pyrexia of unknown origin following delivery. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). Coders also document this condition as mycoplasmal postpartum fever. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complications specified during the puerperium.

Code Identity

ICD-10-CM Code
O86.4
Billable Status
Yes — Valid for Submission
Code Describes
Pyrexia of unknown origin following delivery
Short Description
Pyrexia of unknown origin following delivery
Same as the full description in the CMS dataset.
Parent Code
O86
Other puerperal infections

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO85-O92Complications predominantly related to the puerperium
CategoryO86Other puerperal infections
This CodeO86.4Pyrexia of unknown origin following delivery

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O86.4.

Maternity diagnoses
The Medicare Code Editor detects inconsistencies in maternity cases by checking a patient's age and any diagnosis on the patient's record. The maternity code edits apply to patients age ange is 9–64 years inclusive (e.g., diabetes in pregnancy, antepartum pulmonary complication).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Mycoplasmal postpartum fever
  • Postnatal infection
  • Puerperal pyrexia
  • Puerperal pyrexia of unknown origin
  • Pyrexia of unknown origin

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Puerperal infection NOS following delivery
  • Puerperal pyrexia NOS following delivery

Type 2 Excludes

  • pyrexia during labor O75.2

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.

    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • following delivery
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • puerperal
    • Infection, infected, infective(opportunistic)
      • puerperal
    • Infection, infected, infective(opportunistic)
      • puerperal
        • minor
    • Puerperal, puerperium(complicated by, complications)
      • fever (of unknown origin)
    • Puerperal, puerperium(complicated by, complications)
      • infection
    • Puerperal, puerperium(complicated by, complications)
      • pyrexia (of unknown origin)
    • Pyrexia(of unknown origin)
      • puerperal

Clinical ClassificationClinical

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

CCSR PRG027
Complications specified during the puerperium
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Fever

A fever is a body temperature that is higher than normal. A normal temperature can vary from person to person, but it is usually around 98.6 °F (37 °C). A fever is not a disease. It is usually a sign that your body is trying to fight an illness or infection.

Read the full article at MedlinePlus

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

Convert O86.4 to ICD-9-CMHistory

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

ICD-9-CM
672.02 Puerp pyrexia-del w p/p
Approximate The match is approximate rather than exact.
ICD-9-CM
672.04 Puerp pyrexia-postpartum
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 O86.4Overview

Is O86.4 (Other puerperal infections) a billable code?

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

Who can O86.4 be reported for?

The Medicare Code Editor checks pyrexia of unknown origin following delivery against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.

What is the ICD-9 equivalent of O86.4?

Under the General Equivalence Mappings, pyrexia of unknown origin following delivery converts to ICD-9-CM 672.02 (puerp pyrexia-del w p/p) and 672.04 (puerp pyrexia-postpartum). 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.