ICD-10 Code M05.00 – Felty’s syndrome, unspecified site (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.00 – Felty’s syndrome, unspecified site
What it is
M05.00 identifies Felty’s syndrome when the site is not further specified. It is used for a rheumatoid arthritis-associated condition marked by systemic involvement, with documentation often focusing on the syndrome rather than one joint.
Clinical signs
Clinical features vary; refer to documentation. Standard references describe the syndrome as occurring with rheumatoid arthritis and may include splenomegaly and low white blood cell counts.
When to use this code
Use M05.00 when the provider documents Felty’s syndrome and does not identify a more specific site or related rheumatoid arthritis code. It may appear in records describing longstanding rheumatoid arthritis with systemic complications. Check documentation if the note is unclear or if another rheumatoid arthritis code is better supported.
Do not use for
Do not use this code for rheumatoid arthritis without Felty’s syndrome or when the documentation names a different rheumatoid arthritis subtype. Do not assign it if the syndrome is only suspected; check documentation.
Coding tip
Confirm that Felty’s syndrome is explicitly documented before coding M05.00, and review the record for any more specific rheumatoid arthritis diagnosis.