Diagnosis of paraneoplastic neurologic syndromes (PNS) requires an understanding of the clinical, immunologic and oncologic heterogeneity. The 2004 PNS criteria were partially outdated due to advances in the field, and updated consensus criteria for PNS have been proposed in 2021, including the PNS-Care score for assessment of PNS probability. Furthermore, knowledge on the limitations of autoantibody testing is crucial to ensure accurate interpretation. This review presents the updated diagnostic criteria for PNS, in a Danish context.