Though elevated ESR and/or CRP levels were included as a diagnostic criterion in the 2011 definition of PJI by the Musculoskeletal Infection Society (MSIS) [27] and the 2013 guidelines of the Infectious Diseases Society of America (IDSA) [4], the 2018 Proceedings of International Consensus Meeting (ICM) on Orthopedic Infections underlined that negative test results do not exclude the possibility of infection [28]. This evidence concerns the gene ESR1 and infection.