ICD-10 Code M05.9 – Rheumatoid arthritis with rheumatoid factor, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.9 – Rheumatoid arthritis with rheumatoid factor, unspecified
What it is
This code identifies rheumatoid arthritis when rheumatoid factor is present, but the record does not specify the exact site or subtype. Use it for a documented RA diagnosis with positive rheumatoid factor and no further detail.
Clinical signs
Typical findings include chronic inflammatory joint pain, swelling, stiffness, and reduced range of motion, often affecting small joints symmetrically. Clinical features vary; refer to documentation.
When to use this code
Use M05.9 when the provider documents rheumatoid arthritis with rheumatoid factor and does not specify a more detailed subtype or site. It also fits when the note confirms seropositive RA but leaves the exact joint involvement unspecified. Check documentation if another M05 code is supported.
Do not use for
Do not use this code for rheumatoid arthritis without rheumatoid factor, or when a more specific seropositive RA code is documented. Do not assign it if the chart does not confirm rheumatoid factor positivity.
Coding tip
Code the highest level of specificity available, and verify both rheumatoid factor status and any documented joint or organ involvement.