How axSpA is diagnosed

Disclosing diagnosis

The information in this article refers to the diagnosis of axial spondyloarthritis (axSpA) also known as ankylosing spondylitis (AS). The diagnosis of is axSpA is different to the diagnosis of non-radiographic axial-spondyloarthritis (nr-axSpA). This is because damage to the joints in people with axSpA can be seen on radiographic (x-ray) images. Whereas joint damage can not be seen on x-ray images in people with nr-axSpA. Doctors might diagnose nr-axSpA by the presence of clinical features and inflammation detected on an magnetic resonance imaging (MRI) scan.

To read more about how non-radiographic axial spondyloarthritis (nr-axSpA) is diagnosed please read how is nr-axSpA diagnosed?

Spine x-ray

How is axSpA diagnosed?

There is no definitive test to diagnose axSpA.  If your General practitioner (GP) thinks you may have axSpA they will refer you to a rheumatologist. A rheumatologist is a specialist who is an expert in diagnosing and treating arthritis. Your rheumatologist will take a range of tests to reach a axSpA diagnosis. 

What to expect at a GP appointment?

You will need a referral from your GP to see a rheumatologist. It is important to describe your symptoms in as much detail as possible, so your GP can properly assess you. Your GP may ask you about:

  • How old you were when you first noticed symptoms
  • How long you have had the symptoms for
  • If your symptoms are worse in the morning and improve throughout the day
  • If you have a family history or relatives with axSpA
  • If you have any other conditions or symptoms that could indicate you have axSpA, such as pain in other areas of your body.

What to expect at a rheumatologist appointment?

For a rheumatologist to diagnose you with axSpA they will need to take a range of tests. These tests include a physical examination, investigation of your family history, blood tests, x-rays, and other imaging scans.

Your rheumatologist will:

  • Talk to you about your symptoms, where and when you feel back pain, and whether it feels better or worse when you move.
  • Ask if anyone in you family has had axSpA, back problems or other types of arthritis.
  • carefully examine your spine, eyes, shoulders, hips, knees and feet to check how well they can move, and to look for signs of inflammation such as tenderness, warmth or swelling. You may also be assessed for other symptoms including uveitis (inflammation of the eye), gastrointestinal conditions, like Crohn’s Disease or ulcerative colitis) and fatigue.
  • take a blood sample to help decide if your symptoms are caused by inflammation and to test for the HLA-B27 gene.
  • Send you for an x-ray or other scan such as a CT or an MRI of your spine and pelvis.

What is the HLA-B27 gene?

The HLA-B27 gene is strongly linked to the development of axSpA. About one in eight people with the gene develop axSpA. So even if you have the gene, you may never develop axSpA. If you are suspected of having axSpA your doctor will take a blood test to check whether you have the HLA-B27 gene. Your rheumatologist will use this in conjunction with other tests to determine an axSpA diagnosis.

How to prepare for your appointment?

It is always helpful to prepare for your appointment. This will help you to get the most out of your time with your doctor.  Here are a few suggestions to help prepare:

Delayed or misdiagnosis 

Diagnosing axSpA is not always straightforward and may take longer than you had hoped. On average people wait 5-7 years for a diagnosis from the onset of symptoms. axSpA can be difficult to diagnose for different reasons including:

  • Inflammatory low back can be confused with mechanical back pain. Low back pain is a key feature of AS due to the inflammation of the joints between the tailbone and pelvis, known as the sacroiliac joints. As time goes on pain can become chronic (constant) and can spread to your spine. Low back pain due to AS is inflammatory but may be confused with mechanical back pain (pain that is caused by injury or strain) particularly by doctors who are not familiar with early symptoms of AS. This can lead to delays in diagnosis and treatment.
  • Blood tests are not conclusive. Blood tests can check for inflammatory markers in your body, which if elevated indicate inflammation in the body. However, inflammation can be due to other reasons such as bacterial infection and viruses. Even if a person has active axSpA their levels of inflammation may not be elevated which can cause confusion. Also, it is possible that people can still develop axSpA without having the HLA-B27 gene. This can result in a delay or misdiagnosis because your doctor may not think you have axSpA if you test negative for HLA-B27.
  • Difference in awareness amongst physiciansNot all GPs have the same experience in diagnosing and treating people with axSpA. Which means they may not know what initial symptoms of axSpA to look for. In the early stages of axSpA joint damage may not show up on an imaging test. If you have taken x-rays that are not showing joint damage this could mean have non-radiographic axial spondyloarthritis (nr-axspa), a type of axial spondyloarthritis that doesn’t show up on x-rays. The earlier you receive the correct diagnosis the sooner you will receive appropriate treatment to help manage your axSpA.  

Here are some suggestions that might help you to receive a timelier diagnosis:

  • Don’t let your symptoms be ignored.  If you feel that you are not being listened to by your doctor or that you have been misdiagnosed with a condition that doesn’t match your symptoms, look for another doctor who will refer you to a rheumatologist. It can be frustrating having to search for the right doctor but reaching a diagnosis means you can start appropriate treatment sooner.
  • Keep a diary of your symptoms. Tracking your symptoms is a good way to show your doctor the pattern of your symptoms.
  • See your doctor when you are having a flare (worsening symptoms). Having your doctor visibly see any swelling and inflammation can help them have a better understanding of your symptoms.
  • Don’t assume you don’t have arthritis because of your age. People often mistake arthritis as an ‘old’ person’s disease. However, arthritis can affect anyone at any age. In fact, axSpA is more common in young people with the average onset of the disease under 30 years of age.
  • Try to determine if you have a family history. Many types of inflammatory arthritis have genetic links. Understanding whether you have a family history or not can help contribute to a diagnosis.