Diagnosis of ankylosing spondylitis: tests and examinations

If you encounter lower back pain that lasts for three months or longer, you may have some type of Axial spondylitis (axial SpA) is called Ankylosing spondylitis (as such). AS is an aggressive autoimmune condition, so getting an early diagnosis and starting treatment right away is crucial.

Tests used to diagnose ankylosing spondylitis include a physical exam, medical history, blood tests, genetic tests, and imaging.

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Ankylosing spondylitis symptoms usually begin in the late teens to mid-30s, but anyone can develop it, including children. But because the symptoms start slowly, they are often ignored or confused with other health problems. A 2015 report found that the median diagnostic delay for axial SpA is eight years.

It is not unusual for people with ankylosing spondylitis to see several health care providers to deal with back pain and stiffness that turns out to be AS. These medical professionals can include primary care providers, orthopedic surgeons (specializing in conditions of the musculoskeletal system), physical therapists, and chiropractors.

But the type of healthcare provider who can best diagnose ankylosing spondylitis is Rheumatologist—a physician specializing in the musculoskeletal system and Autoimmune diseases Such as. If you have symptoms suggestive of ankylosing spondylitis, make an appointment to see a rheumatologist or ask your primary health care provider for a referral.

This article discusses tests to diagnose ankylosing spondylitis, including physical, neurological, blood tests, genetic tests, and imaging.

Physical examination for ankylosing spondylitis

A physical examination for AS usually begins with a thorough review of your medical and family history.

Your medical history examines whether your back pain is mechanical or inflammatory. According to the American Spondylitis Association, mechanical back pain is caused by physical changes in the back. It is often the result of daily activities such as heavy lifting, incorrect posture, or poor sleeping positions.

On the other hand, inflammatory back pain associated with ankylosing spondylitis is persistent, lasting more than three months, affecting people under the age of 35, and getting worse after periods of inactivity. Inflammatory back pain will improve with movement and exercise Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen.

In addition to understanding the nature of your back pain, your healthcare provider will want to know when your symptoms began and what exacerbates and improves them. They also want to know about systemic symptoms (those that affect the entire body) and other joint pain in the neck, hips, shoulders, arms, and legs.

It is helpful to share every detail about your symptoms and general health to help your healthcare provider make an accurate diagnosis.

The HLA-B27 gene, which can lead to AS, is inherited. Moreover, family and twin studies have shown that AS has a strong genetic component. You should inform your healthcare provider if AS or other autoimmune diseases run in your family.

Once your healthcare provider has information about your medical and family history, they will want to perform a thorough physical and neurological examination.

You will be asked to flex your back and hips in different directions during the physical exam to check for stiffness and pain. They may also press on some areas of the body to look for sore spots.

Since labored breathing is a sign of severe AS, your healthcare provider will also check your breathing. The breathing problems in ankylosing spondylitis result from scarring of the lung due to inflammation, the forward arching of the upper body, and the stiffness of the chest wall.

A neurological exam evaluates sensory and motor functions, including reflexes and muscle strength. Your healthcare provider will also review other neurological symptoms, such as nerve pain, numbness, tingling, muscle weakness or spasms, and bowel and bladder dysfunction.

Blood tests for ankylosing spondylitis

Blood work can look for signs ignition AS suggest. This is also done to rule out other conditions. Blood tests aren’t enough to confirm AS, but they help your healthcare provider understand your symptoms.

There are no specific tests to confirm AS, but some blood tests can check for signs of inflammation and rule out other conditions that cause similar symptoms.

The following blood tests may be ordered if AS is suspected:

  • sedimentation rate (ESR or sedimentation rate): An ESR test detects inflammation in the body. ESR is a measure of how quickly red blood cells settle in a test tube.
  • C-reactive protein (CRP): CRP is a protein made by the liver. High levels of C-reactive protein are an indication of a condition that causes inflammation.
  • A comprehensive blood test (CBC): The CBC test checks the number of blood cells. A high white blood cell count and a low red blood cell count indicate inflammation usually associated with AS.
  • Rheumatoid factor (RF): RF is often associated with other autoimmune arthritis conditions such as Rheumatoid arthritis And the lupus. RF testing is ordered to rule out these conditions when AS is suspected.

Genetic testing for ankylosing spondylitis

A genetic blood test may be ordered to see if you carry the HLA-B27 gene. According to 2018 report, this gene is only present in 8% of the general population. HLA-B27 is present in 90% of people with ankylosing spondylitis.

Testing positive for HLA-B27 does not mean that you will continue to develop AS. Only about 5% to 6% of people who have the gene will develop AS, according to a 2019 study. Report in the journal Orthopedic Research.

If you carry the HLA-B27 gene, your healthcare provider will likely suspect ankylosing spondylitis. This gene is also associated with more severe symptoms of AS, such as eye inflammation and a condition called iritis (Inflammation of the middle layer of the eye wall tissue).

Ankylosing spondylitis imaging tests

Various imaging studies can help diagnose ankylosing spondylitis, including conventional rays (X ray) , MRI (magnetic resonance imaging), Tomography (CT), and ultrasound. X-rays are standard for diagnosing ankylosing spondylitis, while a CT scan, MRI scan or ultrasound may be ordered to assess the bones and soft tissues of the spine in more detail.

If your healthcare provider orders imaging, they may look for the following signs of AS:

  • Sacroiliitis (inflammation of one or both SI joints)
  • Loss cartilage In the joints (Located between the vertebrae) which may lead to fusion
  • Loss of the normal curvature of the spine kyphosis (hunchback) or Lordosis Favorite
  • Spinal and pelvic fractures
  • Bone erosion (bone loss) in the lower back
  • bony growth in the vertebrae
  • calcification (hardening of the bones)

Your healthcare provider may use X-rays and MRIs to track the progression of AS or to look for fractures or joint damage.

Confirm the diagnosis of ankylosing spondylitis

Your health care provider will rely on your physical and neurological exams, history of symptoms, imaging results, and blood work to diagnose AS.

According to 2020 rheumatism; report, a healthcare provider can make a diagnosis of AS based on specific criteria, which include:

  • Back symptoms: It includes back pain that has lasted for three or months and started before the age of forty, which goes away with exercise and gets worse in the morning and after periods of inactivity, back pain that turns into pain in the buttocks, and limited movement of the lower back.
  • Get relief with NSAIDs, which suggests that back pain is caused by inflammation
  • Peripheral manifestations such as arthritis in the arms, legs and shoulders. ductile (swelling of the fingers and toes), f Enthesitis (Inflammation of the ligaments – sites where tendons and ligaments attach to bones)
  • musculoskeletal manifestations, such as uveitis, psoriasis (a chronic skin condition), and Inflammatory bowel disease
  • Positive family history of AS
  • HLA-B27 positive
  • High levels of CRP and ESR
  • Evidence of sacroiliitis on imaging
  • osteitis (osteoarthritis) and/or Bone marrow edema (fluid buildup in the bone marrow), which can be seen on an MRI

If you’ve had inflammatory back pain for at least three months or longer, along with other characteristics that are part of the criteria for diagnosing AS, your healthcare provider will likely diagnose you with AS.


Ankylosing spondylitis is an autoimmune disease that occurs when the immune system malfunctions and attacks healthy tissue — especially the small bones in the spine. AS is an aggressive condition and early diagnosis is critical to reducing spinal complications, such as spinal fusions, fractures, and abnormal curvatures.

If you have signs and symptoms of ankylosing spondylitis, such as pain and stiffness in the lower back and hips, contact your healthcare provider so they can order testing to determine the cause. Tests used to diagnose ankylosing spondylitis include physical and neurological exams, blood tests, genetic tests, and imaging.

Ankylosing spondylitis is usually diagnosed based on symptoms, blood work, imaging results, and HLA-B27 positivity.

Word from Verywell

Ankylosing spondylitis is a lifelong condition. There is no cure for this disease, but it is treatable and manageable.

You will have several options for treating your condition, which can reduce symptoms and prevent disease progression. Taking your medications as prescribed is essential to slowing the effects of the disease on you, maintaining your mobility and independence, and maintaining a good quality of life.

In addition to following your treatment plan, you should see your rheumatologist regularly. And be sure to talk about whether your treatment plan is not adequately managing your symptoms.

Frequently Asked Questions

  • What are the early warning signs of ankylosing spondylitis?

    The first signs of ankylosing spondylitis are pain and stiffness in the lower back and hips, especially in the morning and after periods of inactivity. You may also experience neck pain and fatigue. Over time, these symptoms will get worse or better during seizures (exacerbation of disease) and remission (no symptoms).

  • Do I need to see a specialist for ankylosing spondylitis test?

    If you have symptoms of ankylosing spondylitis, your primary care provider may refer you to a rheumatologist. A rheumatologist is specially trained to diagnose and treat disorders such as AS that affect joints, muscles, connective tissues, and bones.

  • What happens after ankylosing spondylitis is diagnosed?

    After receiving an ankylosing spondylitis diagnosis, you’ll want to work with your healthcare provider to create a treatment plan. You will be prescribed medications and given information about lifestyle habits to help manage your symptoms, such as diet changes, exercise, and adaptive aids to reduce joint stress.

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