What is a normal rheumatoid factor level?

A normal rheumatoid factor (RF) level is typically less than 14 IU/mL (international units per milliliter) for most laboratories. However, it’s important to note that having a high RF level doesn’t necessarily mean that a person has rheumatoid arthritis or another autoimmune disease. Additionally, some people with rheumatoid arthritis may have a normal RF level, so RF testing is just one of several tools that doctors use to diagnose autoimmune diseases. Ultimately, the interpretation of RF levels depends on a person’s medical history, symptoms, and other laboratory test results.