Rheumatoid Factor

Rheumatoid factor is an antibody that is directed at the Fc portion of an IgG. It is sensitive for rheumatoid arthritis but not specific, and so if you get a positive rheumatoid factor result, think of other diseases or situations that can cause it to be positive. See the mnemonic above which I learned after Dr. Zickuhr's lecture as referenced below. Rarely, rheumatoid factor can be positive in healthy adults too!