With back pain as one of the most common complaints in the population and with no single disease feature with sufficient sensitivity and specificity to diagnose axial spondyloarthritis (axSpA) on... Show moreWith back pain as one of the most common complaints in the population and with no single disease feature with sufficient sensitivity and specificity to diagnose axial spondyloarthritis (axSpA) on its own, diagnosing axSpA can be challenging. In this article, we discuss clinical, laboratory, and imaging spondyloarthritis features that can be used in diagnosis and explain the general principles underlying an axSpA diagnosis. Moreover, we discuss three pitfalls to avoid when diagnosing axSpA: i) using classification criteria as diagnostic criteria, ii) making a diagnosis by simple counting of spondyloarthritis features, and iii) overreliance on imaging findings. Finally, we have some advice on how to build diagnostic skills and discuss new developments that may help facilitate the diagnosis of axSpA in the future.(c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4.0/). Show less