Rheumatoid factor

A rheumatoid factor (RF) test checks a sample of your blood for rheumatoid factor, a protein made by the immune system.

RF testing is mostly used with other tests to help diagnose rheumatoid arthritis. Rheumatoid arthritis (RA) is a type of autoimmune disorder that damages your joints and causes pain, swelling, and stiffness. It is a chronic (long-lasting) condition that can also affect your organs and cause other symptoms.

Source: MedlinePlus, U.S. National Library of Medicine

Normal range

1 published range, each from a named source

14 IU/mL drawn: all ages · ARUP Laboratories Test Directory

Normal: 0–14 IU/mL

Ranges from ARUP Laboratories Test Directory.

details

Sample: Serum or plasma · LOINC
Code: LOINC 11572-5 · IU/mL
Also known as: Fact, Fac, Rheum

See your own Rheumatoid factor Add a lab report and it is drawn against your lab's range, over time. Upload a Blood Test