ICD-10 Code B39.9 – Histoplasmosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B39.9 – Histoplasmosis, unspecified
What it is
B39.9 identifies histoplasmosis when the record confirms Histoplasma infection but does not specify the site, severity, or form. Use it for an unspecified fungal infection caused by Histoplasma.
Clinical signs
Clinical features vary; refer to documentation. Commonly noted findings may include fever, cough, fatigue, chest discomfort, or evidence of pulmonary or disseminated fungal disease.
When to use this code
Use B39.9 when the provider documents histoplasmosis without naming a specific manifestation such as pulmonary, disseminated, or mediastinal disease. It also fits when the chart confirms Histoplasma infection but lacks enough detail for a more specific code.
If the note includes a defined site or complication, code that more specific form instead. Check documentation when histoplasmosis is mentioned only as a differential diagnosis or historical problem.
Do not use for
Do not use B39.9 for a documented specific histoplasmosis type, such as pulmonary or disseminated disease. Do not assign it when histoplasmosis is only suspected or ruled out.
Coding tip
Look for the exact provider wording; if the site is stated, choose the specific histoplasmosis code instead of unspecified B39.9.