C Protein, also known as C-reactive protein (CRP), is a substance produced by the liver in response to inflammation. It is part of the body's immune response and can be measured in the blood. Elevated levels of C Protein can indicate the presence of inflammatory conditions, infections, or chronic diseases. Doctors often use C Protein tests to help diagnose and monitor conditions such as rheumatoid arthritis, lupus, and infections. While it is a useful marker for inflammation, it does not specify the exact cause, so further testing may be needed to determine the underlying issue.