Under updated RA criteria, diagnosis can be supported by involvement of which pattern?

• A. Three large joints
• B. One small joint
• C. One large joint or 2+ small joints involved
• D. 2–3 joints in a symmetrical pattern

Answer: (C)

The pattern that supports diagnosis under the updated RA criteria is either involvement of a single large joint or involvement of two or more small joints. This reflects that rheumatoid arthritis can present in different ways: a solitary large joint can still contribute to an RA diagnosis when other domains (serology, inflammatory markers, duration) are favorable, while involvement of two or more small joints is a classic sign that strengthens the RA score on its own. The other patterns don’t fit this joint-involvement framework as cleanly: multiple large joints without any small joints doesn’t align with how the criteria weight joint patterns, a single small joint by itself is usually not enough to meet the threshold, and a symmetrical pattern of only 2–3 joints doesn’t capture the specific pathways the criteria use to accumulate points for RA.