Auto-antibodies

Understanding the Rheumatoid Factor (RF) and its relationship with Rheumatoid Arthritis (RA) isn’t as easy as the names imply. You might think that a positive RF test result spells out RA without a doubt, but as with most things autoimmune, it’s not that simple.

The Rheumatoid Factor autoantibody

The Rheumatoid Factor is an autoantibody, which means it’s a protein produced by our immune system that mistakenly attacks our own tissues. Our immune system is constantly producing autoantibodies, however we also have a built-in regulatory system that finds these autoantibodies and destroys them – making sure they don’t cause trouble. When an autoimmune condition, like Rheumatoid Arthritis develops, it’s because our regulatory system is faltering and isn’t doing a good job of getting rid of autoantibodies and other autoimmune factors. 

Let’s explore how this simple blood test has revolutionized the early detection of rheumatoid arthritis (RA), offering new hope and insights for patients and practitioners alike.

Understanding the Anti-CCP Test

Let’s start with the basics. The anti-CCP test is a crucial diagnostic tool used in the evaluation of RA. But what exactly does it measure, and why is it so important? The test detects the presence of autoantibodies (antibodies that attack your own body) against a class of proteins that have undergone citrullination. Citrullination is a process in which the amino acid arginine is converted into citrulline, one of many ways our body is able to produce this vital amino acid. 

Coming to a diagnosis of Rheumatoid Arthritis (RA) can be easy. We are spared months of bouncing between doctors and tests if we have the “right” symptoms and the “right” labs. Unfortunately, for many, the road to a RA diagnosis isn’t quite so quick. This is most commonly seen when the Rheumatoid Factor (RF) is positive but the anti-cyclic citrullinated peptide antibody (anti-CCP) is negative. 

As we’ve spoken about before, the RF antibody blood test is far from perfect. Despite its name, the Rheumatoid Factor is not specific for RA. In fact, it is seen in many other medical conditions (including the condition of “getting older”). Usually ordered with a RF (and if not with, then usually immediately afterwards) is the anti-CCP antibody. This antibody is MUCH more specific for RA and is seen in individuals years before developing RA symptoms. After 20+ years of practice, it is now standard of care to order an anti-CCP when concerned about RA. And our dependence on it can lead many to be confused when it returns negative.