Fig. 2.

The diagnostic scale and weights of diagnostic test results for axial spondyloarthritis

The balanced scale (A) indicates an undetermined diagnostic situation, in which other tests are normally needed. Positive and negative test results depending on their weights would change the balance towards more or less likely diagnosis. The weights of the positive and negative diagnostic tests (B) reflected by the size of the balls represent examples based on approximation of the literature data [8]. The real diagnostic weight might be different depending on the region, background population, and referral structures – see article text for further details. An alternative, more likely explanation of symptoms (differential diagnosis), is attributed to the weights of negative test results. SpA: spondyloarthritis.