ICD-10 Logo
ICDxICD-10 Medical Coding
ICD-10 Logo
ICDxICD-10 Medical Coding
ICD 10 CodesDiagnoses
ICD 10 CodesDiagnoses
ICD-10 Logo
ICDxICD-10 Medical Coding

Comprehensive ICD-10-CM code reference with AI-powered search capabilities.

© 2025 ICD Code Compass. All rights reserved.

Browse

  • All Chapters
  • All Categories
  • Diagnoses

Tools

  • AI Code Search
ICD-10-CM codes are maintained by the CDC and CMS. This tool is for reference purposes only.
v1.0.0
ICD-10 Guide
ICD-10 CodesB27.99

B27.99

Infectious mononucleosis, unspecified with other complication

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 B27.99 is a billable code used to indicate a diagnosis of infectious mononucleosis, unspecified with other complication.

Key Diagnostic Point:

Infectious mononucleosis, commonly caused by the Epstein-Barr virus (EBV), is characterized by fever, sore throat, lymphadenopathy, and fatigue. The condition is often diagnosed in adolescents and young adults. The unspecified nature of this code indicates that the specific viral etiology is not documented, and it may encompass cases where complications arise, such as splenic rupture, hepatitis, or secondary infections. Diagnostic methods include serological tests for heterophile antibodies (Monospot test), EBV-specific antibodies, and complete blood count (CBC) to assess lymphocyte levels. Treatment is primarily supportive, focusing on hydration, rest, and analgesics for symptom relief. In severe cases, corticosteroids may be indicated to reduce inflammation. Understanding the nuances of this condition is crucial for accurate coding, especially when complications are present, as they can significantly impact patient management and billing.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in clinical presentation and complications
  • Need for precise documentation of complications
  • Differentiation from other viral infections
  • Potential for misdiagnosis or underreporting of symptoms

Audit Risk Factors

  • Inadequate documentation of complications
  • Failure to specify the viral etiology
  • Inconsistent clinical findings in patient records
  • Lack of follow-up documentation

Specialty Focus

Medical Specialties

Primary Care

Documentation Requirements

Detailed patient history, physical examination findings, and results of diagnostic tests.

Common Clinical Scenarios

Patients presenting with fatigue, sore throat, and lymphadenopathy.

Billing Considerations

Ensure that all complications are documented to support the use of B27.99.

Infectious Disease

Documentation Requirements

Comprehensive lab results, including serological tests and any imaging studies.

Common Clinical Scenarios

Patients with severe symptoms or complications such as splenic rupture.

Billing Considerations

Documentation must clearly differentiate between EBV and other viral infections.

Coding Guidelines

Inclusion Criteria

Use B27.99 When
  • According to ICD
  • 10 guidelines, B27
  • 99 should be used when the specific viral cause of infectious mononucleosis is not documented, and there are complications
  • Coders must ensure that the documentation supports the diagnosis and any complications

Exclusion Criteria

Do NOT use B27.99 When
No specific exclusions found.

Related CPT Codes

86790CPT Code

EBV antibody test

Clinical Scenario

When serological testing is performed to confirm EBV infection.

Documentation Requirements

Document the reason for the test and the results.

Specialty Considerations

Infectious disease specialists should ensure comprehensive lab results are included.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of infectious mononucleosis, enabling better tracking of complications and outcomes. B27.99 provides a mechanism to capture cases with unspecified complications, which was less defined in ICD-9.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of infectious mononucleosis, enabling better tracking of complications and outcomes. B27.99 provides a mechanism to capture cases with unspecified complications, which was less defined in ICD-9.

Reimbursement & Billing Impact

reimbursement.

Resources

Clinical References

  • •
    CDC Infectious Mononucleosis Information

Coding & Billing References

  • •
    CDC Infectious Mononucleosis Information

Frequently Asked Questions

What are the common complications associated with infectious mononucleosis?

Common complications include splenic rupture, hepatitis, and secondary infections such as streptococcal pharyngitis. These complications can significantly impact patient management and should be documented thoroughly.