2026 ICD-10-CM Diagnosis Code A18.09Other musculoskeletal tuberculosis

ICD-10-CM Codes›A00–B99›A15-A19›A18

ICD-10-CM A18.09
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A18.09 is a billable ICD-10-CM diagnosis code for other musculoskeletal tuberculosis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 548 through 550, 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 3 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified connective tissue disease and Tuberculosis.

Code Identity

ICD-10-CM Code
A18.09
Billable Status
Yes — Valid for Submission
Code Describes
Other musculoskeletal tuberculosis
Short Description
Other musculoskeletal tuberculosis
Same as the full description in the CMS dataset.
Parent Code
A18.0
Tuberculosis of bones and joints

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA15-A19Tuberculosis
CategoryA18Tuberculosis of other organs
This CodeA18.09Other musculoskeletal tuberculosis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bacterial tenosynovitis
  • Granulomatous synovitis
  • Infection of musculoskeletal system caused by Mycobacterium tuberculosis
  • Infectious synovitis
  • Mycobacterial myositis
  • Mycobacterial tenosynovitis
  • Myositis caused by Mycobacterium tuberculosis
  • Tuberculous arthritis
  • Tuberculous infection of tendon sheath
  • Tuberculous synovitis
  • Tuberculous tenosynovitis

Tabular List NotesGuidance

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

Inclusion Terms

  • Tuberculous myositis
  • Tuberculous synovitis
  • Tuberculous tenosynovitis

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 MUS025
Other specified connective tissue disease
Default principal diagnosis: inpatient No · outpatient No
CCSR INF001
Tuberculosis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Bone Infections

Like other parts of the body, bones can get infected. The infections are usually bacterial, but can also be fungal. They may spread to the bone from nearby skin or muscles, or from another part of the body through the bloodstream.

Read the full article at MedlinePlus

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

Convert A18.09 to ICD-9-CMHistory

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

ICD-9-CM
015.90 TB bone/joint NOS-unspec
Approximate The match is approximate rather than exact.

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 A18.09Overview

What is the ICD-10 code for other musculoskeletal tuberculosis?

The ICD-10-CM code for other musculoskeletal tuberculosis is A18.09 (sometimes written as A1809). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is A18.09 (Tuberculosis of bones and joints) a billable code?

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

What MS-DRG does A18.09 group to?

When other musculoskeletal tuberculosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 548, 549, 550, 974, 975, 976, with relative weights from 0.8741 to 2.8860 depending on complications. Higher weights mean higher Medicare reimbursement.

Is A18.09 a CC or MCC?

CMS lists A18.09 as a CC (complication or comorbidity) for FY 2026. 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 3 closely related codes in its exclusion list.

What is the ICD-9 equivalent of A18.09?

Under the General Equivalence Mappings, other musculoskeletal tuberculosis converts to ICD-9-CM 015.90 (TB bone/joint NOS-unspec). The mapping is approximate, so confirm the match fits the documentation.