ICD-10 Code B49 – Unspecified mycosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B49 – Unspecified mycosis
What it is
B49 identifies a fungal infection when the specific organism or site is not documented. Use it for mycosis cases that are confirmed but not further classified.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include signs of a fungal infection, but the record should support the diagnosis and not name a more specific mycosis.
When to use this code
Use B49 when the provider documents mycosis, fungal infection, or fungal disease without identifying the type. It is appropriate when the chart confirms a fungal infection but lacks enough detail for a more specific code.
If later documentation identifies the organism, site, or a more specific diagnosis, you should code that condition instead. Check documentation carefully before assigning this unspecified code.
Do not use for
Do not use B49 when a specific fungal infection is documented and coded elsewhere. Do not use it for colonization, exposure, or suspected infection without confirmation.
Coding tip
Choose the most specific fungal code available; use B49 only when the record supports mycosis but gives no further detail.