ICD-10 Code M06.042 – Rheumatoid arthritis without rheumatoid factor, left hand (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M06.042 – Rheumatoid arthritis without rheumatoid factor, left hand
What it is
This code identifies rheumatoid arthritis affecting the left hand when rheumatoid factor is not present. Use it for documented seronegative rheumatoid arthritis involving the left hand joints.
Clinical signs
Typical findings include inflammatory joint pain, swelling, stiffness, and reduced hand function. Clinical features vary; refer to documentation for the specific left-hand joints involved and whether rheumatoid factor testing was negative.
When to use this code
Use this code when the provider documents rheumatoid arthritis without rheumatoid factor and specifies the left hand. It fits notes describing chronic inflammatory arthritis in the left hand, including pain, swelling, or deformity, when the diagnosis is clearly linked to that side.
If the record only says rheumatoid arthritis or does not identify the hand laterality, you need more specific documentation. Confirm that the condition is not being coded from symptoms alone.
Do not use for
Do not use this code for rheumatoid arthritis with rheumatoid factor, other hand sites, or unspecified laterality. Do not assign it for hand pain or swelling without a documented rheumatoid arthritis diagnosis.
Coding tip
Check laterality and serologic status together; both must be documented for accurate code selection.