As ankylosing spondylitis can cause inflammation of sacroiliac joints and spine as well as may involve some organs such as lungs, eyes and heart valves, early diagnosis of this disease is necessary to decide appropriate treatment plan. Positive HLA-B27 maker, family history of ankylosing spondylitis and frequent gastrointestinal infections are the main possible causes of ankylosing spondylitis. Symptoms, medical history, physical examination of the patient and some laboratory investigations are important for diagnosing ankylosing spondylitis.

General family and medical history of the patient is important for diagnosing ankylosing spondylitis as this disease can be hereditary. In the physical examination, the rheumatologist checks for the tenderness and pain along the back, sacroiliac joints, pelvic bones, heels and chest. Limitation in spinal mobility and restriction of chest expansion if any are also checked. The doctor may also ask the information about the history of gastrointestinal infections, history of iritis or uveitis, fatigue due to presence of inflammation and family history of ankylosing spondylitis. Physical examination may include some tests such as Schober test, Gaenslen test and neurologic evaluation.

After physical examination, consult your doctor about the laboratory investigations and imaging tests. Your doctor will prescribe some laboratory tests such as erythrocyte sedimentation rate (ESR) and determination of C-reactive protein (CRP). Elevated results of these tests are indicative of inflammation in the body. Besides this, other tests used for diagnosing ankylosing spondylitis are complete blood count (CBC) which is helpful to detect anemia. Anemia can originate from the chronic inflammation of ankylosing spondylitis. Detection of HLA-B27 is one of the most significant tests for diagnosis. Presence of this gene may not indicate ankylosing spondylitis. But absence of this genetic marker indicates less possibility of this disease.

In addition to these blood tests, urine analysis is important to detect the abnormalities of kidneys. Patients are also evaluated for sign and symptoms of other associated spondyloarthropathies including psoriasis, inflammatory bowel disease (Crohn’s disease or ulcerative colitis) and venereal disease (reactive arthritis or Reiter’s syndrome).

X-ray findings help to detect the changes in affected joints and bones. Other imaging tests like magnetic resonance imaging (MRI) scan and computerized tomography (CT scan) are useful to detect the inflammation and other changes in the joints. These imaging tests can help to evaluate bone and soft tissues in detail. Characteristic bilateral sacroiliac changes can appear as blurry erosions or thickening / hardening of fibrous tissue (sclerosis) on either side of the joint.

After diagnosing ankylosing spondylitis, you may consult your doctor about the treatment plan and cares to be taken.