Post operative prosthetic joint infection (PJI) is the most common cause of failure of total joint arthroplasty, requiring revision surgery, but a gold standard for the diagnosis and the treatment of PIJ is still lacking [1].

SuPAR, the soluble urokinase plasminogen activation receptor, has been recently described as a powerful diagnostic and prognostic tool, able not only to detect sepsis but also to discriminate different grade of sepsis severity [2,3]

This study aimed to examine the diagnostic value of SuPAR in post operative PJI, in order to explore the possible application of this new biomarker in the early diagnosis of PJI.

The level of SuPAR have been measured in PJI patients and controls (patients undergoing prosthesis revision without infection), and correlated with pro and anti inflammatory markers (CRP C-reactive protein, IL-6, IL-1 TNFα, IL-10, IL-12, IL-8, IL1ra and the chemokine CCL2).

Statistical analysis of Receiver Operating Characteristic (ROC) curves and Area Under the Curve (AUC) was performed

As described in Figure 1, serum SuPAR displayed a strongly significative increase in PJI patients compared to not infected controls, and a significative positive correlation with C-reactive protein, IL-6, IL-1 and TNFα and the chemokine CCL2.

SuPAR displayed a very good AUC, significantly higher than CRP and IL-6 AUC

This study clearly show that the measure of Serum level of SuPAR provide a extremely important benefit because it is a precise indicator of bacterial infection, and the addition of SuPAR serum level measurement to classical inflammatory markers can strongly improve the diagnosis of prosthesis joint infection

The authors acknowledge ViroGates, Denmark for providing suPARNOSTIC Standard Kit.

The authors would also acknowledge the Italian Ministero dell’ Istruzione, Università e Ricerca (MIUR) and Italian Ministero della Salute for providing funds for this research project.