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A31.9

A31.9: Mycobacterial infection, unspecified

Billable / specific codeICD-10-CM

A31.9 is a billable, specific ICD-10-CM code for mycobacterial infection, unspecified. It is valid for submission on a claim.

Check A31.9 with the rest of the claim: free scrubber

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Atypical mycobacterial infection NOS
  • Mycobacteriosis NOS

Excludes2 inherited from the categories above A31.9

Not part of this code, but both may be coded when both are present.

Written on A31: Infection due to other mycobacteria

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Alphabetic index entries that lead here

  • Mycobacterium, mycobacterial(infection)
  • Mycobacterium, mycobacterial›anonymous
  • Mycobacterium, mycobacterial›atypical
  • Disease, diseased›photochromogenic›nonpulmonary

Code history

Unchanged in every release from FY2024 to FY2027.

Other codes under A31

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.