ICD-10 Code A31.8 – Other mycobacterial infections (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A31.8 – Other mycobacterial infections
What it is
A31.8 identifies infections caused by mycobacteria that do not fit the more specific ICD-10 categories. Use it for documented nontuberculous mycobacterial disease when the record does not name a different code.
Clinical signs
Clinical features vary; refer to documentation. Patients may have localized or disseminated mycobacterial infection, with findings depending on the site involved and the organism identified.
When to use this code
Use A31.8 when the provider documents an “other mycobacterial infection” or a nontuberculous mycobacterial infection that is not otherwise classified. It is appropriate when the chart supports mycobacterial disease but does not specify a more exact ICD-10 option. Check documentation for the organism and site if available.
Do not use for
Do not use this code for tuberculosis or for a more specific mycobacterial diagnosis that has its own ICD-10 code. If the record only says “infection” without mycobacterial confirmation, check documentation.
Coding tip
Code the most specific documented mycobacterial infection first, and use A31.8 only when no narrower code applies.