ICD-10 Code B27.90: Infectious mononucleosis, unspecified without complication
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).
đź“‹Clinical overview
This ICD-10 code is commonly used when documentation describes infectious mononucleosis. The most accurate code depends on whether the record identifies gammaherpesviral, cytomegaloviral, other, or unspecified mononucleosis and whether complications such as polyneuropathy, meningitis, or another documented complication are present.
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.
đź©şClinical context
- Primary-care, urgent-care, student-health, infectious-disease, emergency, and follow-up documentation where mono-like illness, fatigue, lymphadenopathy, pharyngitis, or viral testing is part of the active assessment.
- Coding workflows where the chart identifies the viral cause or a documented complication pattern that changes final mononucleosis code specificity.
- Evaluation often includes symptom review, exam for lymph-node, liver, or spleen involvement, blood-count or liver-test review, activity restriction counseling, and follow-up planning for prolonged fatigue or complications.
- Documentation usually becomes more specific when the chart identifies EBV or CMV context, or names a neurologic or other complication rather than uncomplicated mononucleosis.
- Specialist context already linked on this page includes Infectious Disease Specialist, General Physician.
🔍Key distinctions
- This ICD-10 family captures infectious mononucleosis across viral-cause and complication patterns rather than a single organism-specific presentation alone.
- Cause detail, such as gammaherpesviral versus cytomegaloviral versus other or unspecified mononucleosis, and complication detail, such as polyneuropathy or meningitis, drive final code specificity inside this family.
- This title preserves unspecified infectious-mononucleosis detail; if the chart identifies the viral cause or complication pattern more clearly, a more specific code may be used.
- Without-complication mononucleosis is coded separately from mononucleosis with neurologic or other documented complications.
- Documentation that describes infectious mononucleosis is coded differently depending on the documented viral cause and whether neurologic or other complications are present.
Code hierarchy
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
Related codes
Sibling codes
Coding guidelines
Common synonyms
Frequently asked questions
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.