2027 ICD-10-CM Diagnosis Code A31.8Other mycobacterial infections

ICD-10-CM Codes›A00–B99›A30-A49›A31

ICD-10-CM A31.8
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

A31.8 is a billable ICD-10-CM diagnosis code for other mycobacterial infections. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 867 through 869, 974 through 976. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 5 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections.

Code Identity

ICD-10-CM Code
A31.8
Billable Status
Yes — Valid for Submission
Code Describes
Other mycobacterial infections
Short Description
Other mycobacterial infections
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 CodeA31.8Other mycobacterial infections

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abscess of spinal subdural space caused by bacterium
  • Abscess of spinal subdural space caused by Mycobacterium
  • Atypical mycobacterial lymphadenitis
  • Bacterial arthritis of sacroiliac joint
  • Bacterial arthritis of vertebral column
  • Bacterial discitis
  • Bacterial duodenitis
  • Bacterial esophagitis
  • Bacterial spondyloarthritis
  • Bacterial tenosynovitis
  • Bilateral keratitis of eyes caused by bacteria
  • Bilateral mycobacterial keratitis
  • Bursitis caused by bacterial infection
  • Cervical atypical mycobacterial lymphadenitis
  • Cervical lymphadenitis
  • Disseminated atypical mycobacterial infection
  • Disseminated Mycobacterium chelonei infection
  • Disseminated Mycobacterium fortuitum infection
  • Disseminated Mycobacterium gordonae infection
  • Disseminated Mycobacteroides abscessus infection
  • Encephalomyelitis caused by bacterium
  • Enthesitis
  • Gastrointestinal infection caused by non-tuberculous Mycobacterium
  • Granuloma of spinal epidural space caused by bacterium
  • Granuloma of spinal epidural space caused by Mycobacterium
  • Granuloma of spinal subdural space caused by bacterium
  • Granuloma of spinal subdural space caused by Mycobacterium
  • Infection caused by Mycobacterium africanum
  • Infection caused by Mycobacterium agri
  • Infection caused by Mycobacterium aichiense
  • Infection caused by Mycobacterium alvei
  • Infection caused by Mycobacterium asiaticum
  • Infection caused by Mycobacterium aurum
  • Infection caused by Mycobacterium austroafricanum
  • Infection caused by Mycobacterium avium
  • Infection caused by Mycobacterium avium brunese
  • Infection caused by Mycobacterium avium subspecies paratuberculosis
  • Infection caused by Mycobacterium borstelense
  • Infection caused by Mycobacterium bovis
  • Infection caused by Mycobacterium branderi
  • Infection caused by Mycobacterium brumae
  • Infection caused by Mycobacterium celatum
  • Infection caused by Mycobacterium chelonei
  • Infection caused by Mycobacterium chitae
  • Infection caused by Mycobacterium chubuense
  • Infection caused by Mycobacterium confluentis
  • Infection caused by Mycobacterium conspicuum
  • Infection caused by Mycobacterium cookii
  • Infection caused by Mycobacterium diernhoferi
  • Infection caused by Mycobacterium duvalii
  • Infection caused by Mycobacterium fallax
  • Infection caused by Mycobacterium farcinogenes
  • Infection caused by Mycobacterium flavescens
  • Infection caused by Mycobacterium fortuitum
  • Infection caused by Mycobacterium gadium
  • Infection caused by Mycobacterium gastri
  • Infection caused by Mycobacterium genavense
  • Infection caused by Mycobacterium gilvum
  • Infection caused by Mycobacterium goodii
  • Infection caused by Mycobacterium gordonae
  • Infection caused by Mycobacterium haemophilum
  • Infection caused by Mycobacterium hassiacum
  • Infection caused by Mycobacterium hiberniae
  • Infection caused by Mycobacterium hodleri
  • Infection caused by Mycobacterium interjectum
  • Infection caused by Mycobacterium intermedium
  • Infection caused by Mycobacterium intracellulare
  • Infection caused by Mycobacterium komossence
  • Infection caused by Mycobacterium lentiflavum
  • Infection caused by Mycobacterium lepraemurium
  • Infection caused by Mycobacterium madagascariense
  • Infection caused by Mycobacterium mageritense
  • Infection caused by Mycobacterium malmoense
  • Infection caused by Mycobacterium microti
  • Infection caused by Mycobacterium moriokaense
  • Infection caused by Mycobacterium mucogenicum
  • Infection caused by Mycobacterium neoaurum
  • Infection caused by Mycobacterium nonchromogenicum
  • Infection caused by Mycobacterium novocastrense
  • Infection caused by Mycobacterium obuense
  • Infection caused by Mycobacterium parafortuitum
  • Infection caused by Mycobacterium peregrinum
  • Infection caused by Mycobacterium phlei
  • Infection caused by Mycobacterium piscium
  • Infection caused by Mycobacterium porcinum
  • Infection caused by Mycobacterium poriferae
  • Infection caused by Mycobacterium pulveris
  • Infection caused by Mycobacterium rhodesiae
  • Infection caused by Mycobacterium scrofulaceum
  • Infection caused by Mycobacterium senegalense
  • Infection caused by Mycobacterium shimoidei
  • Infection caused by Mycobacterium simiae
  • Infection caused by Mycobacterium smegmatis
  • Infection caused by Mycobacterium sphagni
  • Infection caused by Mycobacterium szulgai
  • Infection caused by Mycobacterium terrae
  • Infection caused by Mycobacterium thamnophis
  • Infection caused by Mycobacterium thermoresistibile
  • Infection caused by Mycobacterium tokaiense
  • Infection caused by Mycobacterium triplex
  • Infection caused by Mycobacterium triviale
  • Infection caused by Mycobacterium vaccae
  • Infection caused by Mycobacterium wolinskyi
  • Infection caused by Mycobacterium xenopi
  • Infection caused by Mycobacteroides abscessus
  • Infection causing encephalomyelitis
  • Infection causing granuloma of extradural space of spinal cord
  • Infection causing spondyloarthritis
  • Infection of intervertebral disc caused by Bacteria
  • Keratitis of left eye caused by bacteria
  • Keratitis of right eye caused by bacteria
  • Left mycobacterial keratitis
  • Mycobacterial arthritis
  • Mycobacterial bursitis
  • Mycobacterial colitis
  • Mycobacterial discitis
  • Mycobacterial duodenitis
  • Mycobacterial encephalomyelitis
  • Mycobacterial enteritis of intestine
  • Mycobacterial enteritis of small intestine
  • Mycobacterial esophagitis
  • Mycobacterial gastritis
  • Mycobacterial keratitis
  • Mycobacterial lymphadenitis
  • Mycobacterial myositis
  • Mycobacterial spondyloarthritis
  • Mycobacterial tenosynovitis
  • Mycobacterium avium intracellulare group choroiditis
  • Mycobacterium avium intracellulare, localized
  • Mycobacterium avium-intracellulare gastritis
  • Mycobacterium fortuitum or Mycobacterium peregrinum
  • Mycobacterium senegalense or Mycobacterium conceptionense
  • Mycobacterium tuberculosis or Mycobacterium canettii
  • Mycobacterium xenopi or Mycobacterium celatum
  • Myelitis caused by bacterium
  • Non-tuberculous mycobacterial colitis
  • Non-tuberculous mycobacterial duodenitis
  • Non-tuberculous mycobacterial enteritis of intestine
  • Non-tuberculous mycobacterial enteritis of small intestine
  • Non-tuberculous mycobacterial esophagitis
  • Non-tuberculous mycobacterial gastritis
  • Right mycobacterial keratitis
  • Spinal subdural abscess
  • Subdural abscess

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to A31.8: its own notes plus those printed at A31 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From A31 Infection due to other mycobacteria applies to 5 codes
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
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 A31.8 to ICD-9-CMHistory

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

ICD-9-CM
031.8 Mycobacterial dis NEC
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About A31.8Overview

What is the ICD-10 code for other mycobacterial infections?

The ICD-10-CM code for other mycobacterial infections is A31.8 (sometimes written as A318). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is A31.8 (Infection due to other mycobacteria) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other mycobacterial infections on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does A31.8 group to?

When other mycobacterial infections is the principal diagnosis on an inpatient stay, it groups to MS-DRG 974, 976, 975, 867, 869, 868, with relative weights from 0.6784 to 3.0488 depending on complications. Higher weights mean higher Medicare reimbursement.

Is A31.8 a CC or MCC?

CMS lists A31.8 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 5 closely related codes in its exclusion list.

What is the ICD-9 equivalent of A31.8?

Under the General Equivalence Mappings, other mycobacterial infections converts to ICD-9-CM 031.8 (mycobacterial dis NEC). The mapping is a direct match.