ICD-10 Code M05.16 – Rheumatoid lung disease with rheumatoid arthritis of knee (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.16 – Rheumatoid lung disease with rheumatoid arthritis of knee
What it is
This code identifies rheumatoid arthritis affecting the knee together with rheumatoid lung disease. Use it when the record clearly links the lung manifestation to rheumatoid arthritis, not as separate unrelated diagnoses.
Clinical signs
Clinical features vary; refer to documentation. You may see knee pain, swelling, stiffness, and documented pulmonary involvement such as interstitial or other rheumatoid lung manifestations.
When to use this code
Use this code when the provider documents rheumatoid arthritis of the knee and rheumatoid lung disease in the same encounter or problem list. The diagnosis should show an active relationship between the arthritis and the lung condition. Check documentation if the lung disease is described without a rheumatoid link.
Do not use for
Do not use this code for rheumatoid arthritis of the knee without lung involvement, or for lung disease that is not documented as rheumatoid. If the site or relationship is unclear, check documentation.
Coding tip
Confirm both the joint site and the rheumatoid lung manifestation before assigning M05.16.