The primary objective of this study is to assess the equivalence of a semi-quantitative electrochemical leukocyte esterase test system and off-label use of the Roche Chemstrip leukocyte esterase (LE) test for the diagnosis of periprosthetic joint infection (PJI) in synovial fluid from hip and knee joints. In this study, the qualitative outcome of each of the two methodologies for detecting leukocyte esterase enzyme will be compared. The hypothesis of this study is that the two tests will demonstrate equivalence. The leukocyte esterase enzyme level will also be compared to synovial white blood cell count, which will be considered as a secondary reference.
