[Rheumatoid factor or antinuclear antibodies as incidental finding]

Rheumatoid factor and antinuclear antibodies are detectable in many different conditions and are ordered by various specialities. The interpretation of results, however, is quite complex.The objective of this article is to help apply these tests correctly and enable an accurate interpretation of the test results. Furthermore, we describe the steps in the differential diagnostics for selecting those patients who need to be referred to a rheumatologist.