ICD10BillableValid for clinical use

ICD-10 Code B27.90: Infectious mononucleosis, unspecified without complication

B27.90 is a billable ICD-10 diagnosis code used to classify Infectious mononucleosis, unspecified without complication 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 Certain infectious and parasitic diseases (A00-B99).

Reviewed by HealthAssure Clinical TeamUpdated 21 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 Certain infectious and parasitic diseases (A00-B99).

When is it used?

  • May be used when a clinician documents infectious mononucleosis, unspecified without complication 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
1Certain infectious and parasitic diseases (A00-B99)
block
B25-B34Other viral diseases
category
B27Infectious mononucleosis
category
B27.9Infectious mononucleosis, unspecified
currentB27.9

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

Infectious Disease SpecialistGeneral Physician

Coding guidelines

Common synonyms

Infectious mononucleosis, unspecified without complicationInfectious mononucleosis

Frequently asked questions

Code details

CodeB27.90
SystemICD10
Display nameInfectious mononucleosis, unspecified without complication
ChapterCertain infectious and parasitic diseases (A00-B99)
BlockOther viral diseases

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Mononucleosis, infectious

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.

ICD-10 Code B27.90 for Infectious mononucleosis, unspecified without complication | HealthAssure