Fig. 2From: Differentiating nonradiographic axial spondyloarthritis from its mimics: a narrative reviewLikelihood ratios of SpA features in patients with axSpA*. axSpA = axial spondyloarthritis; CRP = C-reactive protein; ESR = erythrocyte sedimentation rate; HLA = human leukocyte antigen; IBD = inflammatory bowel disease; NSAID = nonsteroidal anti-inflammatory drug; SpA = spondyloarthritis. * Likelihood ratios include both positive and negative (where appropriate) likelihood ratios of SpA features in patients with axSpA and a method of determining the posttest probability of axSpA in patients with chronic back pain, assuming a prevalence of 5% in the group. Adapted from Rudwaleit M, Feldtkeller E, Sieper J. Easy assessment of axial spondyloarthritis (early ankylosing spondylitis) at the bedside. Ann Rheum Dis. 2006;65 (9):1251–1252. Copyright© 2006, BMJ Publishing Group Ltd. & European League Against Rheumatism [20, 21]Back to article page