AS can be difficult to diagnose.
There isn't a single simple test that will diagnose AS. Instead the rheumatologist has to put together all the findings rather like a jigsaw. Read more about tests for diagnosing AS.
It can be particularly difficult to get a diagnosis if you are one of the 5% of people with AS in the UK who are HLA-B27 negative.
In the audio recording below Dr Andrew Keat, consultant rheumatologist discusses some of the difficulties in making a diagnosis.
You can also listen to Hannah talk about her AS diagnosis.