ICD-10 Code M05.639 – Rheumatoid arthritis of unspecified wrist with involvement of other organs and systems (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.639 – Rheumatoid arthritis of unspecified wrist with involvement of other organs and systems
What it is
This code identifies rheumatoid arthritis affecting an unspecified wrist, with documented involvement of other organs or systems. Use it when the wrist site is known, but the side is not specified and extra-articular disease is present.
Clinical signs
Typical findings include inflammatory wrist pain, swelling, stiffness, and reduced range of motion. Clinical features vary; refer to documentation for evidence of systemic involvement such as other organ or body system manifestations.
When to use this code
Use this code when the provider documents rheumatoid arthritis in the wrist and notes involvement of other organs or systems, but does not identify right or left wrist. It also fits when the record supports active rheumatoid disease with extra-articular involvement. If the chart does not clearly state systemic involvement, check documentation.
Do not use for
Do not use this code for rheumatoid arthritis without organ or system involvement, or when the wrist laterality is documented and a more specific code applies. Do not assign it if the diagnosis is uncertain.
Coding tip
Always verify both the wrist laterality and the presence of extra-articular involvement before selecting M05.639.