Bin G, Xinxin Y, Fan L, et al. - The present study was undertaken to investigate the value of serum fibrinogen (FIB) that can be applied to differentiate between periprosthetic joint infection (PJI) and aseptic loosening of the prosthesis, and to ascertain the clinical significance of FIB for analyzing infection outcomes after first-stage surgery. A retrospective study was conducted to include a total of 90 patients who had undergone total knee arthroplasty or total hip arthroplasty revision from January 2015 to August 2019. In 53 patients (group A), PJI was confirmed, and the other 37 patients were diagnosed with aseptic loosening of the prosthesis (group B). This study's finding demonstrate that FIB is an adequate test to aid in diagnosing PJI, and it is not inferior to CRP and ESR in identifying between PJI and aseptic loosening of the prosthesis. It is a particularly beneficial tool in evaluating infection outcomes after first-stage surgery.