Why do a blood test for rheumatoid factor
A blood test for rheumatoid factor is prescribed for the diagnosis of rheumatoid arthritis, sarcoidosis, hepatitis, autoimmune diseases, systemic diseases, acute inflammatory processes. Rheumatoid factor called immunoglobulins that are specific to FC-plot of IgG. In normal blood should be <14 E/ml If the protection system of the body fails, the body's own tissues are perceived by them as foreign cells. Related to immunoglobulin G protein is in such autoantigens against which begins to produce antibodies.
The essence of the analysis is that if blood is found a rheumatoid factor, it will respond to prepared to "test" antibodies. Currently, most laboratories used latex test, rapid diagnostic testing you can perform Carbo-globulin test (Carbo-test). Most often in laboratories find a fraction belonging to the immunoglobulin M. Early and pronounced increase of these immunoglobulins is considered an unfavorable sign and may indicate severe rheumatoid arthritis.
What if analysis for rheumatoid factor positive
Blood for determination of rheumatoid factor pass in the morning, on an empty stomach (after eight to twelve hours from the last meal), at this time you are allowed to drink only clean water. It is recommended the day before blood sampling to refrain from Smoking. The number of RF increases in systemic manifestations of rheumatoid arthritis. With the obvious signs of the disease analysis on the rheumatoid factor can also be negative and will not change for several months.
The test result can be positive not only in rheumatoid arthritis and primary Sjogren's syndrome, a disease with unclear causes - sarcoidosis, various systemic lesions of the connective tissues (dermatomyositis, lupus, scleroderma). A positive result can also cause a chronic infection (syphilis, tuberculosis, chronic hepatitis, malaria), in these cases, the number of antibodies is much lower.
When symptoms similar to symptoms of rheumatoid arthritis, and in case of positive result of the test should immediately contact the doctor. If rheumatoid factor is detected in a healthy person, you should minimize any risk of developing the disease, exclude hypothermia, bad habits, get rid of the possible foci of chronic infection (sinusitis, dental caries).