Clinical sacroiliac tests in ankylosing spondylitis and other causes of low back pain--2 studies.

Independent assessment by 2 observers of 4 tests for sacroiliac (SI) pain in patients with either mechanical/degenerative low back pain (M/D LBP) or ankylosing spondylitis (AS) showed all 4 to be reproducible, but only 2 of them, namely, pressure over the anterior superior iliac spines and pressure over the lower half of the sacrum, gave worthwhile discrimination. Positive results in these 2 tests were significantly associated with definite AS but also with the combination of low back pain, the HLA B27 antigen, and normal or near normal radiographs, a condition we have called presumptive ankylosing spondylitis.