ICD-10 Code M05.172 – Rheumatoid lung disease with rheumatoid arthritis of left ankle and foot (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.172 – Rheumatoid lung disease with rheumatoid arthritis of left ankle and foot
What it is
This code identifies rheumatoid arthritis affecting the left ankle and foot, with associated rheumatoid lung disease. Use it when both joint involvement and pulmonary involvement are documented together.
Clinical signs
Documentation may note chronic inflammatory arthritis in the left ankle or foot plus rheumatoid lung findings such as interstitial lung disease, pulmonary nodules, or pleural involvement. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider clearly links rheumatoid lung disease to rheumatoid arthritis and specifies the left ankle and foot as involved joints. The record should support both the pulmonary manifestation and the joint laterality.
If the lung disease is documented without rheumatoid arthritis, or the arthritis involves a different site, this code is not appropriate. Check documentation for the exact anatomic site and any stated rheumatoid manifestation.
Do not use for
Do not use this code for rheumatoid arthritis without lung involvement, or for lung disease unrelated to rheumatoid arthritis. Do not assign it if the affected joint is not the left ankle and foot.
Coding tip
Confirm both the rheumatoid lung disease and the left ankle/foot laterality in the provider note before assigning M05.172.