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v1.0.0
ICD-10 Guide
ICD-10 CodesB40.9

B40.9

Blastomycosis, unspecified

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

Code Description

ICD-10 B40.9 is a billable code used to indicate a diagnosis of blastomycosis, unspecified.

Key Diagnostic Point:

Blastomycosis is a systemic fungal infection caused by the dimorphic fungus Blastomyces dermatitidis, primarily affecting the lungs but can disseminate to other organs. The infection is endemic in certain regions of North America, particularly around the Great Lakes and the Ohio and Mississippi River valleys. Patients may present with a variety of symptoms, including cough, fever, night sweats, and weight loss. In severe cases, it can lead to pneumonia or disseminated disease affecting the skin, bones, and central nervous system. Diagnosis is typically made through clinical evaluation, imaging studies, and laboratory tests, including culture and histopathological examination. Treatment usually involves antifungal medications such as itraconazole or amphotericin B, especially in immunocompromised patients who are at higher risk for severe disease. The unspecified nature of this code indicates that the specific site of infection or severity is not documented, which can complicate treatment decisions and patient management.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in clinical presentation and severity of the disease.
  • Need for accurate documentation of symptoms and treatment response.
  • Differentiation from other fungal infections with similar presentations.
  • Potential for misclassification if the site of infection is not specified.

Audit Risk Factors

  • Inadequate documentation of clinical findings.
  • Failure to specify the site of infection.
  • Misuse of unspecified codes when more specific codes are available.
  • Inconsistent treatment documentation, especially in immunocompromised patients.

Specialty Focus

Medical Specialties

Infectious Disease

Documentation Requirements

Detailed clinical notes on symptoms, diagnostic tests, and treatment plans.

Common Clinical Scenarios

Patients presenting with respiratory symptoms and a history of exposure in endemic areas.

Billing Considerations

Consideration of immunocompromised status and potential for disseminated disease.

Pulmonology

Documentation Requirements

Pulmonary function tests, imaging studies, and treatment response documentation.

Common Clinical Scenarios

Patients with chronic cough and pulmonary nodules on imaging.

Billing Considerations

Differentiation from other pulmonary infections and conditions.

Coding Guidelines

Inclusion Criteria

Use B40.9 When
  • Follow the official ICD
  • CM coding guidelines, ensuring that the code is used only when the specific site of infection is not documented

Exclusion Criteria

Do NOT use B40.9 When
  • Review the inclusion and exclusion criteria for accurate coding

Related CPT Codes

87481CPT Code

Fungal culture

Clinical Scenario

Used when a fungal infection is suspected and cultures are taken.

Documentation Requirements

Document the reason for the culture and any relevant clinical findings.

Specialty Considerations

Infectious disease specialists may require additional documentation on treatment response.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of fungal infections, improving the accuracy of data collection and reimbursement. B40.9 serves as a catch-all for unspecified cases, but coders should strive for specificity when possible.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of fungal infections, improving the accuracy of data collection and reimbursement. B40.9 serves as a catch-all for unspecified cases, but coders should strive for specificity when possible.

Reimbursement & Billing Impact

reimbursement. B40.9 serves as a catch-all for unspecified cases, but coders should strive for specificity when possible.

Resources

Clinical References

  • •
    CDC - Blastomycosis

Coding & Billing References

  • •
    CDC - Blastomycosis

Frequently Asked Questions

What are the common symptoms of blastomycosis?

Common symptoms include cough, fever, night sweats, and weight loss. In severe cases, it can lead to pneumonia or disseminated disease.

How is blastomycosis diagnosed?

Diagnosis is made through clinical evaluation, imaging studies, and laboratory tests, including culture and histopathological examination.

What antifungal treatments are used for blastomycosis?

Antifungal treatments include itraconazole for mild to moderate cases and amphotericin B for severe cases or in immunocompromised patients.