The Albumin to Globulin Ratio Performs Well for Diagnosing Periprosthetic Joint Infection: A Single-Center Retrospective Study.

BACKGROUND:Accurate diagnosis of the periprosthetic joint infection (PJI) remains a challenge for surgeons. The purpose of this study was to assess the value of albumin to globulin ratio (AGR) and globulin (GLB) for diagnosing PJI. METHODS:A total of 182 patients undergoing revision after arthroplasty were included and divided into 2 groups, 61 in knee group (PJI: 38; non-PJI: 23) and 121 in hip group (PJI: 26; non-PJI: 95). We used receiver operating characteristic curves to determine the diagnostic value of AGR, GLB, inflammatory markers (erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP]). RESULTS:The receiver operating characteristic curves showed the areas under the curve of AGR, GLB, ESR, and CRP in the knee group were 0.940, 0.928, 0.867, and 0.848, respectively, and they were 0.855, 0.831, 0.886, and 0.912 in the hip group. The optimal predictive cut-off values for AGR in knee and hip groups were 1.375 and 1.295, respectively. The sensitivity and specificity of AGR, respectively, were 94.7% and 87.0% (knee group) and 84.6% and 75.8% (hip group) for diagnosing PJI. The sensitivity of "AGR or ESR" and specificity of "AGR and GLB" in the knee group were 99.6% and 98.9%, respectively. CONCLUSION:For knee or hip groups, the AGR exhibits good value for the diagnosis of PJI comparable with ESR and CRP. The AGR and GLB, together with CRP and ESR, should be used as the preferred indicators for diagnosing PJI. The "AGR or ESR" and "AGR and GLB" in the knee group have an excellent diagnostic value in sensitivity and specificity, respectively.