Ankylosing Spondylitis Information on Risk Factors & Treatment
There is no single specific test to confirm a diagnosis of ankylosing spondylitis. Your physician will most likely complete a thorough physical examination to rule out other causes for your symptoms. The major diagnostic tools used when AS is suspected are magnetic resonance imaging (MRI), X-rays of the spine, which will reveal specific changes in the spine and blood tests to check for inflammation and for the presence of the characteristic genetic marker of ankylosing spondylitis.
An x-ray can reveal changes in the joints caused by AS, but many times these changes are not visible on a plain x-ray until ankylosing spondylitis has been progressing for 8-10 years.
Magnetic resonance imaging tests may lead to an earlier diagnosis, but the reliability of MRIs in diagnosing AS has not been firmly established.
During an acute flare-up of the disease, some AS patients will have an increase of certain blood components (CRP and ESR). But in other patients who have an extreme amount of inflammation with ankylosing spondylitis, these levels do not increase. So these blood tests alone are not an accurate diagnostic tool.
People with the HLA-B27 gene are at greater risk of developing AS than the general population. A blood test for this genetic marker can help in the diagnosis of ankylosing spondylitis, but alone, it is not a diagnosis, as not everyone with this marker develops AS.