Ankylosing Spondylitis Tests

Ankylosing Spondylitis (AS) is a chronic inflammatory autoimmune disease that primarily affects the spine and sacroiliac joints. To properly diagnose ankylosing spondylitis, doctors use a combination of clinical examination, blood tests, and imaging techniques. The diagnosis can be challenging because symptoms such as back pain and stiffness are common in several other conditions. Here’s a detailed overview of the various tests and diagnostic procedures used to confirm ankylosing spondylitis.

The condition or diagnosis is related to the patient’s back issues. The interaction appears to be part of a consultation focused on understanding and addressing spinal health concerns.

 HLA-B27 Test

• HLA-B27 Gene Test: The HLA-B27 gene test is often used in diagnosing ankylosing spondylitis. The HLA-B27 gene is found in about 90-95% of individuals with AS, making it a key genetic marker. However, not all individuals with HLA-B27 will develop ankylosing spondylitis, and not all individuals with AS will test positive for HLA-B27. Thus, it is not definitive on its own but can support the diagnosis.
• How It Helps: A positive test for HLA-B27 increases the likelihood of having AS, especially when combined with symptoms such as chronic back pain and morning stiffness. However, the HLA-B27 test is typically used alongside other diagnostic tests for a more accurate diagnosis.

Blood Tests for Ankylosing Spondylitis

• Inflammatory Markers: Common blood tests include measuring C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), both of which are markers of inflammation in the body. These tests are often elevated in individuals with ankylosing spondylitis during active disease, though they are not specific to AS.
  • CRP: A protein that increases in response to inflammation.
  • ESR: A measure of how quickly red blood cells settle at the bottom of a test tube, which is faster when there is inflammation.
• ANA Test: Antinuclear antibodies (ANA) are tested to rule out other autoimmune conditions. The ANA test is not commonly used to diagnose ankylosing spondylitis, but it can help differentiate AS from other systemic diseases.
• Other Blood Tests: While not definitive for ankylosing spondylitis, tests for other autoimmune markers such as rheumatoid factor (RF) or anti-CCP may be conducted to rule out diseases like rheumatoid arthritis.

Imaging Tests for Ankylosing Spondylitis

• X-rays: X-rays of the spine and sacroiliac joints are commonly used to diagnose ankylosing spondylitis. Early in the disease, X-rays may show sacroiliitis (inflammation of the sacroiliac joints). In advanced cases, fusion of the vertebrae may be visible, known as a bamboo spine.
• MRI Scans: MRI can provide a more detailed view of the spine and sacroiliac joints and is particularly useful in detecting early-stage inflammation that may not yet be visible on X-rays. MRI is more sensitive for detecting active inflammation in the joints and the spine and can help monitor disease progression.
• CT Scans: While CT scans are not commonly used for diagnosing ankylosing spondylitis, they may be employed in certain cases to further evaluate bone damage or joint involvement.

Physical and Clinical Tests

• Chest Expansion Test: One of the hallmark symptoms of ankylosing spondylitis is a reduction in chest expansion due to spinal fusion. A chest expansion test measures how much the chest can expand during breathing. A decreased range of motion is indicative of spinal involvement in AS.
• Schober Test: This test measures the flexibility of the lower back and is used to assess the degree of spinal stiffness. A decreased range of motion in the lower back suggests ankylosing spondylitis.
• Bilateral Sacroiliac Joint Palpation: Palpating the sacroiliac joints for tenderness is used in the clinical examination. Tenderness in these joints is often a sign of sacroiliitis, a common feature of ankylosing spondylitis.

Genetic Testing for Ankylosing Spondylitis

• Genetic Testing: Aside from the HLA-B27 test, genetic testing is not typically used for routine diagnosis, but it may be used to assess genetic predisposition. The presence of HLA-B27 is a major risk factor for AS, though other genetic markers are also believed to contribute to the disease.

Diagnosis and Differential Diagnosis

The diagnosis of ankylosing spondylitis is based on a combination of clinical signs, blood tests, and imaging findings. The presence of HLA-B27, along with the typical symptoms such as chronic back pain and morning stiffness, supports the diagnosis. However, other conditions like rheumatoid arthritis, psoriatic arthritis, and inflammatory bowel disease must be ruled out through further testing.

After a diagnosis of ankylosing spondylitis, managing symptoms is crucial for improving quality of life. Curapod, a device that uses electrical stimulation, can be an important complementary tool in managing ankylosing spondylitis symptoms, particularly pain, muscle stiffness, and inflammation. Curapod helps relax muscles, improve blood circulation, and reduce pain, which can be particularly helpful during flare-ups or in conjunction with physical therapy. Whether used in combination with medications or physical rehabilitation, Curapod enhances mobility and promotes muscle recovery, providing non-invasive relief for patients with ankylosing spondylitis.

References (Cardiff Harvard Style)

1. Mayo Clinic, 2025. Ankylosing Spondylitis: Symptoms and Causes. Available at: https://www.mayoclinic.org/diseases-conditions/ankylosing-spondylitis/diagnosis-treatment/drc-20352477 [Accessed 1 February 2025].
2. American College of Rheumatology, 2025. Ankylosing Spondylitis: Diagnosis and Treatment. Available at: https://www.rheumatology.org/Practice-Tools/Diseases-and-Conditions/Ankylosing-Spondylitis [Accessed 21 February 2025].
3. Spine-Health, 2025. Ankylosing Spondylitis: Symptoms, Causes, and Treatment. Available at: https://www.spine-health.com/conditions/neck-pain/ankylosing-spondylitis [Accessed 21 February 2025].
4. Chiropractic Scientist, 2022. Blood Test for Diagnosis of Ankylosing Spondylitis. Available at: https://chiropracticscientist.com/blood-test-diagnosis-ankylosing-spondylitis-chiropractic-scientist/ [Accessed 20 February 2025].