Ankylosing spondylitis (AS) is an inflammatory condition that affects the spine and large joints, including the hips and shoulders. It is a type of autoimmune disease where the body's immune system mistakenly attacks healthy tissue.
Inflammatory markers are substances produced by the body in response to inflammation. These markers can be detected in a blood test and are often used to help diagnose and monitor autoimmune diseases, such as ankylosing spondylitis.
In AS, inflammatory markers such as the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and interleukin-6 (IL-6) are typically raised. The level of these markers is usually correlated with the severity of the disease. For example, a high CRP level is usually associated with more severe disease activity and a higher risk of complications.
It is important to note that elevated inflammatory markers are not exclusive to AS. Other conditions, such as infections, can also cause them to rise. Therefore, a positive result from a blood test does not necessarily mean that a person has AS. To confirm a diagnosis, a healthcare professional will need to consider additional factors, such as a person's medical history, physical examination, and imaging tests.