Reducing Diagnostic Delay in Axial Spondyloarthritis: Could Lipocalin 2 Biomarkers Help?

Early diagnosis and therapy in axial spondyloarthritis, axSpA, is known to reduce long-term morbidity. However, the time from symptom onset to diagnosis is typically delayed by several years, and this situation has not improved in recent years despite greater clinical awareness and better imaging. This narrative review discusses the underlying causes for axSpA diagnostic delay. It is proposed that to reduce axSpA diagnostic delay, a better understanding of the axSpA subclinical inflammatory process is required, together with machine learning-enabled inflammation/repair biomarkers such as lipocalin 2 and lipocalin 2-matrix metalloprotease 9, developed through extensive clinical domain knowledge.