What does rheumatoid factor indicate?

Answer 1

The normal range for rheumatoid factor is less than 20 (this is dependent on the laboratory). The following disordersAdjustment disorder

Anorexia nervosa

Asperger syndrome

Autism

Autoimmune disorders

Bipolar disorder

Bleeding disorders

Borderline personality disorder

Copd (chronic obstructive pulmonary disorder)

Chronic motor tic disorder

Conversion disorder

are associated with an elevated rheumatoid factor:

Rheumatoid arthritis 26 to 90 percent

Sjgren's syndrome 75 to 95 percent

Mixed connective tissue disease 50 to 60 percent

Mixed cryoglobulinemiaCryoglobulinemia - of the fingers

(types II and III) 40 to 100 percent

SystemicSystemic lupus erythematosus

Systemic lupus erythematosus rash on the face

lupus erythematosus 15 to 35 percent

Polymyositis/dermatomyositis five to 10 percent

This test is not traditionally used for screening purposes as it has a low yield in healthy populations. With this elevated level, further testing is necessary to confirm a diagnosis. An elevated rheumatoid factor by itself is not enough for a diagnosis.


A rheumatoid factor blood test measures the amount of the RF antibody in the blood.
Rheumatoid Factor test may be reported in either "titers" or "units":

" A titer" is a measurement of how far a sample of blood can be diluted before RF can no longer be detected. A titer of "1:20" means that RF can be detected when 1 part of the blood sample is diluted by up to 20 parts of saline. the larger the second number in the titre the larger the RF factor.
"Nephelometry" units indicate the amount light that is blocked by the blood sample. Samples with a high level of RF are cloudier then normal, and as a result less light passes through the tube than when the RF level is low. therefore in the case of the RF test the higher number indicates the higher RF. for example. an RF level of 90 units is higher than one of 40 units.


Normal values depend on what lab is doing the tests. Results are usually available within 2 days.
Rheumatoid factor (RF) Titers 1:20 to 1:80
NephelometryUnits 14 units/mL to 60 units/mL

You should find out from your doctor to see what are normal ranges for the lab that tested your blood.

High RF often acompany

Rheumatoid arthritis. 80% of those aflicted with RA have a positive (RF) level.
Hepatitis C infection.
Other autoimmune diseases, such as systemic lupus erythematosus (SLE), scleroderma, Sjögren's syndrome, and vasculitis.
Infectious Diseases, including tuberculosis, mononucleosis, syphilis, and malaria.
Liver diseases, such as cirrhosis and chronic active hepatitis.
Infection of the heart (endocarditis).
Leukemia.