ICD-10 Code M05.442 – Rheumatoid myopathy with rheumatoid arthritis of left hand (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.442 – Rheumatoid myopathy with rheumatoid arthritis of left hand
What it is
This code identifies rheumatoid arthritis affecting the left hand with associated rheumatoid myopathy. Use it when the record shows both inflammatory joint disease and muscle involvement in that hand.
Clinical signs
Findings may include chronic hand pain, swelling, stiffness, reduced range of motion, and weakness related to rheumatoid disease. Clinical features vary; refer to documentation.
When to use this code
Use M05.442 when the provider documents rheumatoid arthritis of the left hand and specifically links it to rheumatoid myopathy. It is appropriate when the left hand is the documented site and muscle involvement is part of the diagnosis. Check documentation if laterality or myopathy is unclear.
Do not use for
Do not use this code for rheumatoid arthritis without documented myopathy, or for involvement of another hand or site. If the record only says weakness or muscle pain without confirmed rheumatoid myopathy, check documentation.
Coding tip
Confirm both the rheumatoid arthritis diagnosis and the left-hand laterality in the provider note before assigning M05.442.