ICD-10 Code M06.079 – Rheumatoid arthritis without rheumatoid factor, unspecified ankle and foot (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M06.079 – Rheumatoid arthritis without rheumatoid factor, unspecified ankle and foot
What it is
This code identifies rheumatoid arthritis affecting the ankle and foot when rheumatoid factor is not present and the exact side is not specified. Use it for inflammatory joint disease documented in those locations.
Clinical signs
Typical findings include joint pain, swelling, stiffness, and reduced range of motion in the ankle or foot. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents rheumatoid arthritis without rheumatoid factor involving the ankle and foot, but does not specify right or left. It also fits when the record supports the diagnosis and location, yet laterality is unavailable or unclear. Check documentation if another site is also named.
Do not use for
Do not use this code for rheumatoid arthritis with positive rheumatoid factor, or when the diagnosis is limited to another joint. Do not assign it if the record only says arthralgia, osteoarthritis, or unspecified foot pain.
Coding tip
Confirm both the seronegative status and the unspecified laterality before choosing M06.079.