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v1.0.0
ICD-10 Guide
ICD-10 CodesB46.9

B46.9

Unspecified mycosis, unspecified.

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

Code Description

ICD-10 B46.9 is a billable code used to indicate a diagnosis of unspecified mycosis, unspecified..

Key Diagnostic Point:

Unspecified mycosis refers to a fungal infection that does not fall into a specific category of mycoses. Fungal infections can range from superficial infections of the skin and nails to systemic infections that affect internal organs. The term 'unspecified' indicates that the exact type of fungal infection has not been determined or documented. Common fungal pathogens include Candida species, Aspergillus species, and dermatophytes. Patients who are immunocompromised, such as those with HIV/AIDS, cancer, or those on immunosuppressive therapy, are at a higher risk for developing severe fungal infections. Symptoms may vary widely depending on the site of infection and can include skin lesions, respiratory symptoms, or systemic signs of infection. Diagnosis typically involves clinical evaluation, laboratory tests, and sometimes imaging studies. Treatment often includes antifungal medications, which may be topical or systemic, depending on the severity and location of the infection. The choice of antifungal therapy is influenced by the specific fungal organism, the patient's immune status, and any underlying health conditions.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Lack of specificity in the diagnosis
  • Variety of potential underlying conditions
  • Need for comprehensive patient history
  • Potential for misdiagnosis with other infections

Audit Risk Factors

  • Insufficient documentation of the type of mycosis
  • Inconsistent clinical findings
  • Failure to document immunocompromised status
  • Lack of follow-up on treatment outcomes

Specialty Focus

Medical Specialties

Infectious Disease

Documentation Requirements

Detailed patient history, laboratory results, and treatment plans.

Common Clinical Scenarios

Patients presenting with fever and rash, or respiratory symptoms with a history of immunosuppression.

Billing Considerations

Ensure documentation reflects the patient's immune status and any previous fungal infections.

Dermatology

Documentation Requirements

Photographic evidence of skin lesions, detailed descriptions of lesions, and treatment history.

Common Clinical Scenarios

Patients with skin lesions suspected to be fungal in origin but not yet confirmed.

Billing Considerations

Document any differential diagnoses considered and the rationale for treatment choices.

Coding Guidelines

Inclusion Criteria

Use B46.9 When
  • Follow official coding guidelines for mycoses, ensuring that documentation supports the unspecified nature of the diagnosis
  • Include relevant patient history and clinical findings to justify the use of B46

Exclusion Criteria

Do NOT use B46.9 When
No specific exclusions found.

Related CPT Codes

87481CPT Code

Infectious agent detection by nucleic acid (DNA or RNA); fungal, direct probe technique

Clinical Scenario

Used when fungal infection is suspected and requires confirmation.

Documentation Requirements

Document the reason for testing and any clinical findings leading to the suspicion of fungal infection.

Specialty Considerations

Infectious disease specialists should ensure that all relevant clinical data is included.

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, but B46.9 remains a useful code for cases where the specific type is not yet determined. It emphasizes the need for thorough documentation to support the unspecified nature of the diagnosis.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of fungal infections, but B46.9 remains a useful code for cases where the specific type is not yet determined. It emphasizes the need for thorough documentation to support the unspecified nature of the diagnosis.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of fungal infections, but B46.9 remains a useful code for cases where the specific type is not yet determined. It emphasizes the need for thorough documentation to support the unspecified nature of the diagnosis.

Resources

Clinical References

  • •
    CDC Fungal Diseases

Coding & Billing References

  • •
    CDC Fungal Diseases

Frequently Asked Questions

When should I use B46.9?

Use B46.9 when a fungal infection is suspected but not specifically identified. Ensure that documentation supports the unspecified nature of the diagnosis.