Rheumatoid arthritis w/o rheumatoid factor, left ank/ft

This code signifies a diagnosis of seronegative rheumatoid arthritis affecting the left ankle and foot. Seronegative means that the rheumatoid factor (RF) blood test is negative, distinguishing it from seropositive RA. The condition is characterized by chronic inflammation of the synovial lining of the joints, leading to pain, swelling, and potential joint damage in the specified anatomical region.

Use this code when documentation clearly states a diagnosis of rheumatoid arthritis, explicitly notes a negative rheumatoid factor, and specifies involvement of the left ankle and/or foot. This code is appropriate for initial diagnoses, exacerbations, or ongoing management of seronegative RA localized to this area. Supporting documentation includes physician notes, laboratory results confirming seronegativity, and imaging reports detailing joint involvement.

• Ensure documentation explicitly states "seronegative" or "rheumatoid factor negative" to differentiate from seropositive RA (M05.-).
• Verify the specific joint involvement; this code is only for the left ankle and foot. Use other M06.0- codes for different anatomical sites.
• Consider sequencing this code as the primary diagnosis if it is the main reason for the encounter, or as a secondary diagnosis if managing complications or related conditions.