A31.9 Mycobacterial infection, unspecified

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Atypical mycobacterial infection NOS
• Mycobacteriosis NOS

Applies from A31 Infection due to other mycobacteria

Excludes2 (not included here)

• leprosy (A30.-)
• tuberculosis (A15-A19)

MS-DRG index

Defines the logic of DRG(s) 867-869 in MDC 18.

Approximate ICD-9-CM (GEMs)

• 031.9 Unspecified diseases due to mycobacteria

Diagnosis Index entries for A31.9

• Disease, diseased › photochromogenic (acid-fast bacilli) (pulmonary) › nonpulmonary
• Mycobacterium, mycobacterial (infection)
• Mycobacterium, mycobacterial (infection) › anonymous
• Mycobacterium, mycobacterial (infection) › atypical

Nearby codes

• A31 Infection due to other mycobacteria
• A31.0 Pulmonary mycobacterial infection
• A31.1 Cutaneous mycobacterial infection
• A31.2 Disseminated mycobacterium avium-intracellulare complex (DMAC)
• A31.8 Other mycobacterial infections
• A31.9 Mycobacterial infection, unspecified (this code)