2026 ICD-10-CM Diagnosis Code A31.0Pulmonary mycobacterial infection

ICD-10-CM Codes›A00–B99›A30-A49›A31

ICD-10-CM A31.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A31.0 is a billable ICD-10-CM diagnosis code for pulmonary mycobacterial infection. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 177 through 179. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Pneumonia (except that caused by tuberculosis).

Code Identity

ICD-10-CM Code
A31.0
Billable Status
Yes — Valid for Submission
Code Describes
Pulmonary mycobacterial infection
Short Description
Pulmonary mycobacterial infection
Same as the full description in the CMS dataset.
Parent Code
A31
Infection due to other mycobacteria

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA30-A49Other bacterial diseases
CategoryA31Infection due to other mycobacteria
This CodeA31.0Pulmonary mycobacterial infection

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Atypical mycobacterial infection of lung
  • Battey disease
  • Disseminated atypical mycobacterial infection
  • Disseminated Mycobacterium kansasii infection
  • Hyperimmune cutaneous reaction to atypical mycobacteria
  • Hyperimmune cutaneous reaction to mycobacterium kansasii
  • Infection caused by Mycobacterium intracellulare
  • Infection caused by Mycobacterium kansasii
  • Infection caused by Mycobacterium malmoense
  • Infection caused by Mycobacterium xenopi
  • Infection of lung caused by Mycobacterium kansasii
  • Infection of lung caused by Mycobacterium malmoense
  • Infection of lung caused by Mycobacterium xenopi
  • Lady Windermere syndrome
  • Mycobacterial pneumonia
  • Mycobacterium kansasii infection of skin
  • Non-tuberculous mycobacterial pneumonia
  • Pulmonary disease caused by Mycobacteria
  • Pulmonary Mycobacterium avium complex infection

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Infection due to Mycobacterium avium
  • Infection due to Mycobacterium intracellulare Battey bacillus
  • Infection due to Mycobacterium kansasii

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Battey Mycobacterium infection
    • Disease, diseased
      • Battey
    • Disease, diseased
      • photochromogenic (acid-fast bacilli) (pulmonary)
    • Infection, infected, infective(opportunistic)
      • lung
        • atypical Mycobacterium
    • Mycobacterium, mycobacterial(infection)
      • atypical
        • pulmonary
    • Mycobacterium, mycobacterial(infection)
      • avium (intracellulare complex)
    • Mycobacterium, mycobacterial(infection)
      • Battey
    • Mycobacterium, mycobacterial(infection)
      • intracellulare (Battey bacillus)
    • Mycobacterium, mycobacterial(infection)
      • kansasii (yellow bacillus)
    • Mycobacterium, mycobacterial(infection)
      • pulmonary (atypical)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR RSP002
Pneumonia (except that caused by tuberculosis)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Mycobacterial Infections

Mycobacteria are a type of germ. There are many different kinds. The most common one causes tuberculosis. Another one causes leprosy. Still others cause infections that are called atypical mycobacterial infections. They aren't "typical" because they don't cause tuberculosis.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert A31.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
031.0 Pulmonary mycobacteria
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About A31.0Overview

Is A31.0 (Infection due to other mycobacteria) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report pulmonary mycobacterial infection on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does A31.0 group to?

When pulmonary mycobacterial infection is the principal diagnosis on an inpatient stay, it groups to MS-DRG 177, 178, 179, with relative weights from 0.7550 to 1.5627 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A31.0?

Under the General Equivalence Mappings, pulmonary mycobacterial infection converts to ICD-9-CM 031.0 (pulmonary mycobacteria). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.