Rheumatoid Factor (RF)
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
- Blood that is very high in
- Age. Some people older than age 65 have a high
- Having had multiple vaccinations or blood transfusions.
What To Think About
- A small number of people have a high RF level
but do not have rheumatoid arthritis. A small number of these people will later
have rheumatoid arthritis.
- A health professional always uses the
results of an RF test along with information gained from a medical history and
physical examination before diagnosing rheumatoid arthritis.
citrullinated peptide (CCP) is an antibody that is found in the blood of more
than half of all people who have rheumatoid arthritis. It is used to confirm a
diagnosis of rheumatoid arthritis.
- Older adults who do not have
rheumatoid arthritis sometimes have a slightly high RF level.
people have rheumatoid arthritis and have a normal level of RF. The RF test may
need to be repeated if rheumatoid arthritis is suspected and the first RF level
- Less than one-third of children who have
juvenile idiopathic arthritis have a high RF level.
Other Works Consulted
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Primary Medical Reviewer
||Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer
||E. Gregory Thompson, MD - Internal Medicine
||June 11, 2010
WebMD Medical Reference from Healthwise
June 11, 2010
This information is not intended to replace the advice of a doctor.
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