The diagnostic value of ratio biomarkers for periprosthetic joint infection

Abstract

Background The diagnosis of periprosthetic joint infection (PJI) remains challenging. Currently, there is no single test marker for PJI that has an acceptable level of sensitivity. To enhance diagnostic accuracy, ratio or combined tests have been introduced. Blood testing is crucial as the first step in clinical testing, so this article aims to improve diagnostic efficiency by combining blood test markers. Methods༚ We conducted a retrospective data collection of 288 patients who underwent total hip or knee joint revision surgery in our hospital from January 2013 to January 2023. A total of 227 patients who met the inclusion criteria were divided into two groups: PJI group (89 cases) and aseptic loosening group (138 cases). Blood test indicators were collected preoperatively as diagnostic indicators for PJI. New diagnostic parameters were formed by combining the indicators through ratios. The diagnostic value of all biomarkers was evaluated using receiver operating characteristic (ROC) curves and area under the curve (AUC), and the optimal cutoff value, positive predictive value (PPV), and negative predictive value (NPV) were further calculated using the Youden index. Results༚ The PJI group showed significantly higher levels of ESR, CRP, PLT, CLR, ELR, PMR, PLR, SII, and CRP/ALB compared to the aseptic loosening group. The diagnostic performance of serum ratio biomarkers including CRP/WBC, CLR, CRP/FIB, CRP/ALB, CRP/GLB, and CRP/AGR were all above 0.900, with AUCs of 0.902, 0.913, 0.900, 0.908, 0.915, and 0.915, respectively, indicating excellent diagnostic value. CRP/ALB and CRP/AGR had higher diagnostic performance than traditional serum biomarkers ESR (AUC = 0.840) and CRP (AUC = 0.913), with sensitivities of 80.9% and 88.8%, and specificities of 89.9% and 83.3%, respectively. Conclusion Compared with traditional markers ESR and CRP, the new ratio combination significantly improved the accuracy and reliability of PJI diagnosis (P < 0.001), among which CRP/ALB and CRP/AGR have good discriminative ability.