What Is C-Reactive Protein? What It Can Tell You About Your Autoimmune Disease

There’s no single test that can give a definitive diagnosis for rheumatoid arthritis and other autoimmune arthritis. In addition to blood tests that measure inflammation, such as the CRP test, and antibodies, rheumatologists look at factors like physical symptoms and imaging, such as X-rays and MRIs. Doctors put these factors together to make a clinical diagnosis, which means they look at the big picture of the disease, rather than a relying on a single test result.The C-reactive protein (CRP) test is one of many blood tests your doctor might order for to help make your diagnosis and throughout your treatment. Here’s what the CRP blood test can — and can’t — reveal about your condition.What Is C-Reactive Protein?Inflammation in the body triggers the liver to create C-reactive proteins, says Stuart D. Kaplan, MD, chief of rheumatology at South Nassau Communities Hospital in Oceanside, New York. Doctors can measure the amount of those proteins through a blood test. The higher the levels...