How is Ankylosing Spondylitis diagnosed?

How is Ankylosing Spondylitis Diagnosed?

Ankylosing Spondylitis (AS) is a chronic inflammatory disease that primarily affects the spine, causing pain, stiffness, and eventually leading to fusion of the vertebrae. Early diagnosis and treatment are crucial to managing the symptoms and preventing long-term complications. Diagnosing AS involves a combination of medical history, physical examination, imaging tests, and laboratory tests.

Medical History

The first step in diagnosing AS is a detailed medical history. The doctor will ask about your symptoms, their duration, and any family history of AS or other autoimmune diseases. It is important to provide accurate information about your symptoms, including the location and intensity of pain, morning stiffness, and any other associated symptoms.

Physical Examination

During the physical examination, the doctor will assess your range of motion, flexibility, and any signs of inflammation. They may check for tenderness and swelling in the joints, especially in the spine and sacroiliac joints. The doctor may also evaluate your posture and look for any signs of spinal deformity or limited mobility.

Imaging Tests

Imaging tests play a crucial role in diagnosing AS. The most commonly used imaging techniques include:

• X-rays: X-rays can reveal changes in the spine and sacroiliac joints, such as fusion, erosion, and new bone formation. However, these changes may take time to develop, so early-stage AS may not be visible on X-rays.


• Magnetic Resonance Imaging (MRI): MRI uses powerful magnets and radio waves to create detailed images of the spine and other affected areas. It can detect inflammation and early structural damage even before it appears on X-rays, making it a valuable tool for early diagnosis.


• Computed Tomography (CT) Scan: CT scans provide detailed cross-sectional images of the spine and can help identify bony changes, especially in the later stages of AS.

Laboratory Tests

Laboratory tests are not definitive for diagnosing AS, but they can help support the diagnosis and rule out other conditions. The most commonly ordered tests include:

• Blood Tests: Blood tests can measure certain markers of inflammation, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Elevated levels of these markers may indicate ongoing inflammation in the body.


• Genetic Testing: A specific genetic marker called HLA-B27 is present in the majority of individuals with AS. However, having HLA-B27 does not necessarily mean you have AS, as it can also be found in other conditions.

Consultation with a Rheumatologist

AS is a complex condition that requires specialized knowledge for accurate diagnosis and management. If your primary care physician suspects AS based on your medical history, physical examination, and initial tests, they may refer you to a rheumatologist. Rheumatologists are doctors who specialize in diagnosing and treating autoimmune and inflammatory diseases, including AS. They will further evaluate your symptoms, review the test results, and make a definitive diagnosis.

Monitoring and Follow-up

Once diagnosed with AS, regular monitoring and follow-up with a rheumatologist are essential. AS is a chronic condition that requires ongoing management to control symptoms, prevent complications, and maintain a good quality of life. Your rheumatologist will develop a personalized treatment plan based on the severity of your symptoms, disease progression, and your overall health.

In conclusion, diagnosing Ankylosing Spondylitis involves a comprehensive approach that includes medical history, physical examination, imaging tests, and laboratory tests. Early diagnosis is crucial for timely intervention and effective management of the disease. If you suspect you may have AS, it is important to consult with a healthcare professional for a proper evaluation and diagnosis.