Busch A, Jäger M, Engler H, et al. - Researchers sought to determine the diagnostic accuracy of serum and synovial fluid Procalcitonin (S-PCT and SF-PCT) for periprosthetic joint infection (PJI) in orthopedic surgery and compared it with the biomarkers recommended in the 2018 Definition of periprosthetic hip and knee infection. They conducted a prospective cohort study including 70 cases with painful hip, shoulder and knee arthroplasty from August 2018 to July 2019. Of these cases, 23 (33%) were classified as the PJI group and 47 (67%) as the aseptic group. The 2018 Definition of periprosthetic hip and knee infection was used to diagnosed PJI. They obtained preoperative blood and synovial joint fluid to determine PCT measures. Observations revealed no reliable value of S-PCT and SF-PCT as alternative biomarker in the differential diagnosis of PJI from aseptic loosening in total joint arthroplasty. Further, the data gained could not confirm the frequently described high sensitivity of alpha-1-Defensin in PJI diagnosis.