If a person comes to the doctor with stiff, aching joints that may be swollen and feel warm, then the CCP IgG blood test may be ordered. This blood test is one of the ways to determine if rheumatoid arthritis is causing the condition or if there is another connective tissue disorder involved that is causing the bothersome symptoms. The rheumatoid factor can be measured based on antibodies that are present, attacking the IgG within the blood, and this leads a doctor to make an RA diagnosis.
Sometimes this test will be ordered if only some of the symptoms of RA are present. Fever, fatigue, and intermittent pain around the joints that improves over the course of the day can also be potential symptoms of this disease.
What Do the CCP IgG Blood Test Results Mean?
Although lab results may vary slightly from person to person, a positive result for CCP antibodies typically means that there is a very good chance that rheumatoid arthritis is present. The odds are even higher when there is CCP and RF detected.
A positive result may also indicate that there is the presence of another erosive disease other than RA. High levels of CCP antibodies have also been discovered in connective tissue diseases, autoimmune disorders, and particularly with some forms of lupus.
If the test results indicate the presence of RF without CCP antibodies, there are antibodies without RF, or both are present but in low levels, then this may be an indication of early RA.
How Reliable is the CCP IgG Blood Test?
Although the CCP IgG blood test can help to measure RF and determine that antibodies are indeed present, it is not a conclusive test that can provide a definitive diagnosis. Doctors will use this blood test in conjunction with other tests to positively identify the presence of RA. Rheumatoid arthritis affects about 1% of the total population, but as few as 1 in 2 people who have RA will actually have a positive CCP IgG blood test result.
RF can also be found in patients that don’t have rheumatoid arthritis at all. False positives are also known to happen in about 5% of tests when a person would be classified as healthy. When studied, about 7 out of 10 patients with RA will have a positive CCP IgG blood test. In random testing of blood donors and control samples, about 2 out of 100 will test positive.
In some control studies, the false positive rate has been as high as 10%. There have also been rare instances where a positive CCP test occurred, but it was because of the presence of active hepatitis C.
Because of this, a positive result on the CCP IgG blood test will not trigger a diagnosis or treatment plan based on that information alone. A full examination of a patient’s history and other tests are often required to confirm the suspicions that RA is present. These additional tests may be ordered even when test results are negative since there is a chance that RA may be present, but the blood test did not detect antibodies or RF.
The CCP IgG Blood Test Is Often Ordered In a Series
If the CCP IgG blood test results are required for a diagnosis, then it is very common to have a series of tests ordered to definitely determine that rheumatoid arthritis is present. Tests to determine if inflammation is present, but not detectable by the patient, are commonly ordered. If one hasn’t been completed recently, a complete blood count may be ordered to see if there are high numbers of white blood cells present.
Another concern for doctors when RA is present is anemia, so testing to determine if it is present is also common. Antinuclear antibody testing may also be ordered if RA is suspected to rule out other autoimmune disorders. About 1 in 3 people who have RA will test positive for the antinuclear antibody test.
The CCP IgG blood test may also be ordered to monitor RA treatment progress in conjunction with other tests. No specific test preparations are required for this test. It can be performed the same day it is ordered. If the test results come back as positive, then discuss with a doctor what the implications of that result means. Although not definitive, a positive result usually means rheumatoid arthritis is present and needs to be treated.