2026 ICD-10-CM Diagnosis Code M02.369Reiter's disease, unspecified knee

ICD-10-CM Codes›M00–M99›M00-M02›M02

ICD-10-CM M02.369
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M02.369 is a billable ICD-10-CM diagnosis code for Reiter's disease, unspecified knee. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 545 through 547. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Immune-mediated/reactive arthropathies.

Code Identity

ICD-10-CM Code
M02.369
Billable Status
Yes — Valid for Submission
Code Describes
Reiter's disease, unspecified knee
Short Description
Reiter's disease, unspecified knee
Same as the full description in the CMS dataset.
Parent Code
M02.36
Reiter's disease, knee

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM00-M02Infectious arthropathies
CategoryM02Postinfective and reactive arthropathies
This CodeM02.369Reiter's disease, unspecified knee

Code EditsBilling

Medicare Code Editor checks that affect claim validity for M02.369.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Clinical ClassificationClinical

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

CCSR MUS008
Immune-mediated/reactive arthropathies
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Infectious Arthritis

Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Infectious arthritis is an infection in the joint. The infection comes from a bacterial, viral, or fungal infection that spreads from another part of the body. Symptoms of infectious arthritis include:

Read the full article at MedlinePlus

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

Convert M02.369 to ICD-9-CMHistory

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

ICD-9-CM
099.3 Reiter's disease
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
711.16 Reiter arthritis-l/leg
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

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 M02.369Overview

Is M02.369 (Reiter's disease, knee) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report Reiter's disease, unspecified knee on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M02.369 group to?

When Reiter's disease, unspecified knee is the principal diagnosis on an inpatient stay, it groups to MS-DRG 545, 546, 547, with relative weights from 0.8362 to 2.4817 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M02.369?

Under the General Equivalence Mappings, Reiter's disease, unspecified knee converts to ICD-9-CM 099.3 (Reiter's disease) and 711.16 (reiter arthritis-l/leg). The mapping is approximate, so confirm the match fits the documentation.

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.