CRP and psoriasis: According to the 2009 Assessment of SpondyloArthritis international Society (ASAS) axial spondyloarthritis (SpA) classification criteria, a diagnosis of axial SpA can be made when a patient presents with back pain lasting for more than 3 months, combined with imaging evidence of sacroiliitis, along with any one of the SpA features such as HLA-B27 positivity, elevated CRP and ESR, inflammatory back pain, or psoriasis [10].