ICD-10 Code M05.87 – Other rheumatoid arthritis with rheumatoid factor of ankle and foot (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.87 – Other rheumatoid arthritis with rheumatoid factor of ankle and foot
What it is
This code identifies rheumatoid arthritis with a positive rheumatoid factor that affects the ankle and foot, but does not fit a more specific rheumatoid arthritis subtype. Use it when documentation links the disease to these joints.
Clinical signs
Typical findings include inflammatory joint pain, swelling, stiffness, and reduced range of motion in the ankle or foot. Clinical features vary; refer to documentation for the exact joint involvement and rheumatoid factor status.
When to use this code
Use this code when the provider documents rheumatoid arthritis with rheumatoid factor involving the ankle and foot and specifies it as “other” rheumatoid arthritis. It is appropriate when the record does not support a more specific M05 code. Check documentation if laterality or additional joint details are unclear.
Do not use for
Do not use it for rheumatoid arthritis without rheumatoid factor, or for cases documented only as unspecified arthritis. Do not assign it when the condition is better described by a more specific rheumatoid arthritis code.
Coding tip
Confirm both the rheumatoid factor finding and the ankle/foot involvement in the provider note before assigning M05.87.