Ankylosing spondylitis is diagnosed by taking a careful history, reviewing the family history and careful examination of the spine. There is no direct test for ankylosing spondylitis and it may take several visits to the doctor and accurate reporting of symptoms, over a period of time before a definitive diagnosis is made. Very often, in active disease, infl ammatory markers like the ESR and CRP are raised. In majority of AS patients the gene HLA-B27 is present. X-rays of the spine and MRI are often helpful in confirming the diagnosis.