What is the normal range for RA factor?

The normal range for RF factor in the blood is typically less than 40 to 60 units per milliliter, according to MedlinePlus. Some labs may also report it as a titer of less than 1 to 80. Testing for rheumatoid factor requires giving a blood sample.

The RF test is used to help diagnose rheumatoid arthritis or Sjogren's syndrome. A low RF can mean a patient does not have those conditions, but some people with rheumatoid arthritis or Sjogren's syndrome have a normal amount of RF in the blood, states MedlinePlus. The higher the RF level, the more likely the patient has one of the two conditions.