High RF (Positive RF) 

A raised RF result can indicate the presence of an autoimmune condition.
Clinically, a high RF is most commonly associated with rheumatoid arthritis, but may also occur in other autoimmune diseases, chronic infections, or inflammatory conditions. Elevated RF is considered a supportive marker when investigating inflammatory joint symptoms, but not diagnostic on its own.  

Low or Negative RF 

A normal or low RF result suggests that rheumatoid factor is not elevated.
This makes rheumatoid arthritis less likely, but does not rule it out, as many patients with early or seronegative rheumatoid arthritis can have a normal RF. Consider the use of broader autoimmune test panels, and that a low RF result is interpreted alongside symptoms and other markers.