2026 ICD-10-CM Diagnosis Code M79.0Rheumatism, unspecified
ICD-10-CM Codes›M00–M99›M70-M79›M79
- Billable — Valid for Submission
- Not Chronic
M79.0 is a billable ICD-10-CM diagnosis code for rheumatism, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 555 through 556. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified connective tissue disease.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Fibroblastic rheumatism
- Hand rheumatism
- Psychosomatic rheumatism
- Rheumatism
- Rheumatism, excluding the back
- Rheumatology disorder monitoring status
- Rheumatology disorder treatment changed
- Rheumatology disorder treatment started
- Rheumatology symptom change
- Secondary autoimmune hemolytic anemia
- Secondary autoimmune hemolytic anemia co-occurrent and due to rheumatic disorder
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
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.
- Rheumatism(articular) (neuralgic) (nonarticular)
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Connective Tissue Disorders
Your connective tissue supports many different parts of your body, such as your skin, eyes, and heart. It is like a "cellular glue" that gives your body parts their shape and helps keep them strong. It also helps some of your tissues do their work. It is made of many kinds of proteins. Cartilage and fat are types of connective tissue.
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Convert M79.0 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M79.0Overview
Is M79.0 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report rheumatism, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M79.0 group to?
When rheumatism, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 555, 556, with relative weights from 0.8306 to 1.3218 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M79.0?
Under the General Equivalence Mappings, rheumatism, unspecified converts to ICD-9-CM 729.0 (rheumatism NOS). 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.
