ICD-10-CM 2027
ICD-10 code for polyarthritis
From the official ICD-10-CM alphabetic index entry “Polyarthritis, polyarthropathy”. Page updated September 29, 2026.
About coding polyarthritis
The ICD-10-CM code for polyarthritis is M13.0 (Polyarthritis, unspecified). The official index lists 4 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on M13.0.
Within M13, choose M13.0 (Polyarthritis, unspecified) only when documentation doesn't support a more specific option: monoarthritis, not elsewhere classified (M13.1) and other specified arthritis (M13.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 553 (Bone Diseases and Arthropathies with MCC, relative weight 1.2494) and DRG 554 (Bone Diseases and Arthropathies without MCC, relative weight 0.8331), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific polyarthritis codes (official index)
- due to or associated with other specified conditions
- epidemic (Australian) (with exanthema) B33.1 — Ross River disease
- infective
- inflammatory M06.4 — Inflammatory polyarthropathy
- juvenile (chronic) (seronegative) M08.3 — Juvenile rheumatoid polyarthritis (seronegative)
- migratory M13.8 — Other specified arthritis
- rheumatic, acute
Common questions about polyarthritis ICD-10 codes
What is the ICD-10 code for polyarthritis?
- M13.0 — Polyarthritis, unspecified. More specific codes apply when the documentation supports them: B33.1, M06.4, M08.3, M13.8.
What is the ICD-10 code for epidemic polyarthritis?
- B33.1 — Ross River disease.
What is the ICD-10 code for inflammatory polyarthritis?
- M06.4 — Inflammatory polyarthropathy.
What is the ICD-10 code for juvenile polyarthritis?
- M08.3 — Juvenile rheumatoid polyarthritis (seronegative).
What is the ICD-10 code for migratory polyarthritis?
- M13.8 — Other specified arthritis (header code; choose a more specific subcode).
Is M13.0 billable?
- Yes. M13.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can M13.0 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict M13.0 as a principal diagnosis.
Is M13.0 a CC or MCC?
- No. M13.0 is neither a CC nor an MCC under MS-DRG v44.0.