ICD-10 Code M05.849 – Other rheumatoid arthritis with rheumatoid factor of unspecified hand (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.849 – Other rheumatoid arthritis with rheumatoid factor of unspecified hand
What it is
This code identifies rheumatoid arthritis with rheumatoid factor affecting a hand, but the hand is not specified as right or left. Use it when documentation confirms rheumatoid factor positivity and hand involvement, without a more specific site.
Clinical signs
Typical findings include inflammatory joint pain, swelling, stiffness, and reduced hand function. Clinical features vary; refer to documentation for the exact joint pattern, laterality, and any recorded rheumatoid factor evidence.
When to use this code
Use this code when the provider documents rheumatoid arthritis with rheumatoid factor and indicates hand involvement, but does not specify which hand. It is also appropriate when the record supports rheumatoid arthritis in an unspecified hand and no laterality detail is available.
Check documentation if the note mentions multiple joints, generalized rheumatoid arthritis, or a different anatomic site. If the hand is specified as right or left, code the laterality-specific option instead.
Do not use for
Do not use this code for rheumatoid arthritis without rheumatoid factor, or when the affected hand is clearly documented as right or left. Do not assign it if the condition is in another joint or if documentation is too vague; check documentation.
Coding tip
Confirm both rheumatoid factor status and unspecified hand laterality before assigning M05.849.