Clinical history as a screening test for ankylosing spondylitis.

A controlled study of 138 subjects demonstrated that the clinical history may be sensitive (95%) and specific (85%) in the differential diagnosis of ankylosing spondylitis when reliance of five specific historic features is made. Back pain that is insidious in onset, in a patient younger than 40 years, persisting for at least three months, associated with morning stiffness and improving with exercise is characteristic of inflammatory spinal disease.