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M05.771 vs M05.779

M05.771 (Rheumatoid arthritis with rheumatoid factor of right ankle and foot without organ or systems involvement) compared with M05.779 (Rheumatoid arthritis with rheumatoid factor of unspecified ankle and foot without organ or systems involvement), from the official CMS tabular data. M05.771 and M05.779 code the same condition on opposite sides.

Relationship

Review

Laterality relationship

M05.771
Right
Rheumatoid arthritis with rheumatoid factor of right ankle and foot without organ or systems involvement
M05.779
Unspecified
Rheumatoid arthritis with rheumatoid factor of unspecified ankle and foot without organ or systems involvement

Same condition; these differ only in which side is documented.

These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.

Source: ICD-10-CM tabular list (laterality variant derived from the code title)

Can these codes be reported together?

Same condition, opposite side. M05.771 and M05.779 name the same condition on opposite sides of the body.

Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.

Side by side

M05.771Rheumatoid arthritis with rheumatoid factor of right ankle and foot without organ or systems involvementM05.779Rheumatoid arthritis with rheumatoid factor of unspecified ankle and foot without organ or systems involvement
Billing statusBillableBillable
ClassificationM00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)
DefinitionRheumatoid arthritis with rheumatoid factor of right ankle and foot without organ or systems involvement is a billable ICD-10-CM diagnosis code (M05.771).Rheumatoid arthritis with rheumatoid factor of unspecified ankle and foot without organ or systems involvement is a billable ICD-10-CM diagnosis code (M05.779).

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources