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ICD-10 Code O86.4: Pyrexia of unknown origin following delivery

O86.4 is a billable ICD-10 diagnosis code used to classify Pyrexia of unknown origin following delivery in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Pregnancy, childbirth and the puerperium (O00-O9A).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Pregnancy, childbirth and the puerperium (O00-O9A).

When is it used?

  • May be used when a clinician documents pyrexia of unknown origin following delivery in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
15Pregnancy, childbirth and the puerperium (O00-O9A)
block
O85-O92Complications predominantly related to the puerperium
category
O86Other puerperal infections
currentO86

Official coding notes

Inclusion terms
  • Puerperal infection NOS following delivery
  • Puerperal pyrexia NOS following delivery
Excludes2 (may code together if documented)
  • pyrexia during labor (O75.2)

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

ObstetricianGynecologistGastroenterologist

Related tests

Complete blood count
Commonly reviewed when evaluating postpartum fever.
Urinalysis
May be reviewed when postpartum fever raises concern for urinary infection.
Urine culture
May be used when postpartum fever prompts infection workup.

Related procedures

Pelvic ultrasound
May appear in selected postpartum infection or fever workups when retained tissue or pelvic collections are being evaluated.

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
O86.4

Common synonyms

Pyrexia of unknown origin following delivery

Frequently asked questions

Code details

CodeO86.4
SystemICD10
Display namePyrexia of unknown origin following delivery
ChapterPregnancy, childbirth and the puerperium (O00-O9A)
BlockComplications predominantly related to the puerperium

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)Infection, infected, infective(opportunistic)Infection, infected, infective(opportunistic)Puerperal, puerperium(complicated by, complications)Puerperal, puerperium(complicated by, complications)Puerperal, puerperium(complicated by, complications)Pyrexia(of unknown origin)

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.