Making the diagnosis in prosthetic joint infection: a European view

Key aInfecƟon is only likely if there is a posiƟve clinical feature or raised serum CRP together with another posiƟve test (synovial fluid, microbiology, histology or nuclear imaging). bExcept in adverse local Ɵssue reacƟon (ALTR) and crystal arthropathy cases. cshould be interpreted with cauƟon when other possible causes of inflammaƟon are present: gout or other crystal arthropathy, metallosis, acƟve inflammatory joint disease (e.g. rheumatoid arthriƟs), periprostheƟc fracture or the early postoperaƟve period. dThese values are valid for hips and knee PJI. Parameters are only valid when clear fluid is obtained and no lavage has been performed. Volume for the analysis should be >250 μL, ideally 1 mL, collected in an EDTA containing tube and analyzed in <1h, preferenƟally using automated techniques. For viscous samples, pretreatment with hyaluronidase improves the accuracy of opƟcal or automated techniques. In case of bloody samples, the adjusted synovial WBC= synovial WBC observed – [WBC blood / RBC blood x RBC synovial fluid] should be used.