What is the best cutoff point of leukocyte esterase for diagnosis of periprosthetic joint infections? a systematic review and meta-analysis.

Background: Periprosthetic joint infection (PJI) is a significant complication following total joint arthroplasty that demands rapid, accurate diagnosis. The leukocyte esterase (LE) test shows promise, but studies vary in cut-off values and omit the centrifugation's effect. In this study, we assessed the sensitivity and specificity of the LE test across different cut-off values, both with and without centrifugation. We aimed to identify the optimal threshold for diagnosing PJI and to compare its diagnostic odds ratio (DOR) to those of biomarkers recommended by the International Consensus Meeting (ICM).

Methods: A comprehensive literature search was performed in PubMed, Scopus, Web of Science, and Embase up to May 2024. Studies were included if they evaluated the diagnostic accuracy of LE for PJI in TJA and provided sufficient data for constructing 2 × 2 contingency tables. Data extraction and quality assessment were independently conducted by two reviewers using a standardized form and the QUADAS-2 tool. Statistical analysis involved pooling data using a bivariate random-effects model and constructing summarized receiver operating characteristic (sROC) curves.

Results: Out of 2195 records, 26 studies involving 4,206 joints (1,282 with PJI) were included. The optimal LE cut-off point without centrifugation was 3 + , yielding a sensitivity of 0.877, a specificity of 0.957, and a DOR of 159.2. With centrifugation, a 2 + cut-off provided a sensitivity of 0.899, a specificity of 0.924, and a DOR of 108.6. Direct comparison with other biomarkers indicated that polymorphonuclear neutrophils percentage (PMN%), white cell count (WCC), and alpha defensin (AD) had a slightly higher diagnostic odds ratio and Youden index than LE. Direct comparison with other biomarkers also indicated that erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP), synovial CRP, and D-dimer had lower DOR and Youden index than LE.

Conclusions: The LE test is an effective diagnostic tool for PJI. Adopting a 3 + cut-off point without centrifugation and a 2 + one with centrifugation optimizes diagnostic accuracy.