Diagnosing early ankylosing spondylitis.

Diagnosis of ankylosing spondylitis is still delayed by many years. Several efforts have been made in the past few years to shorten this delay. A new set of criteria for inflammatory back pain has performed better than previous sets. MRI has evolved to become the standard imaging modality for the detection of sacroiliitis during early disease, and it clearly outperforms quantitative scintigraphy, which was the standard screening test for many years. Promising new developments such as whole body MRI and ultrasound (sonography) for the detection of enthesitis or sacroiliitis deserve further evaluation. Serum antibodies directed against a 28-kD Drosophila antigen may provide additional diagnostic information. A recently proposed diagnostic algorithm in patients with suspected early ankylosing spondylitis may help physicians confidently diagnose patients before definite radiographic sacroiliitis is detectable. Finally, referral strategies for patients seen by primary care physicians seem to work well and are currently under further valuation.