CORR Insights®: Does the Alpha Defensin ELISA Test Perform Better Than the Alpha Defensin Lateral Flow Test for PJI Diagnosis? A Systematic Review and Meta-analysis of Prospective Studies

摘要

Periprosthetic joint infection (PJI) remains a major clinical problem and there are several unmet needs, including better diagnostic tests. PJI has also been recognized as a high research priority in the field of musculoskeletal infection [9]. To address this problem, research during the past 5 years has identified alpha-defensin (AD) produced by neutrophils in synovial fluid as a faithful biomarker of local infection [1]. Clinically, AD in synovial fluid can be measured quantitatively in a laboratory with an ELISA test developed by CD Diagnostics (Claymont, DE, USA). There is also a new qualitative point-of-care test using a lateral flow device (Synovasure®, Zimmer-Biomet, Warsaw, IN, USA) that can provide a result within 10 minutes. To establish that the lateral flow test for AD has the same diagnostic abilities as the “gold standard” ELISA test, which has an established sensitivity of 95% to 100% and specificity of 95% to 97%, Kuiper et al. [2] performed a meta-analysis of published studies using these tests, based on Preferred Reporting Items for Systematic reviews and Meta-Analyses [3] guidelines. They found no differences between the ELISA and lateral flow tests in the pooled cohorts (THA and TKA combined). The sensitivity was 90% versus 86% (p = 0.43), and specificity was 97% versus 96% (p = 0.39). The authors also found that the pooled sensitivity of the AD lateral flow test did not differ between THA and TKA (80% versus 87%; p = 0.20). Although the authors reported a difference in sensitivity for the diagnosis of PJI between the THA and TKA groups for the AD ELISA test (70% versus 94%; p = 0.008), they cautioned that their results must be carefully interpreted because the pooled data were heterogenous and only two studies were included in this group.