Prosthetic joint infection (PJI) poses a significant burden on patients, clinicians and the healthcare economy. Although various tests have been established for the diagnosis of PJI, the diagnosis remains challenging. In this review, established and potential future diagnostic tests are presented, some of which could provide stepping stones towards improved diagnosis, identification of aetiological agents and efficacious therapeutic options for the management of PJI. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.