The American Musculoskeletal Infection Society (MSIS) in 2014 included serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) as secondary diagnostic criteria for PJI (Parvizi, Gehrke & International Consensus Group on Periprosthetic Joint Infection, 2014); thus, diagnostic accuracy of PJI was improved. Here, CRP is linked to juvenile polyposis syndrome.