Cooper KB, Siegel ER, Stambough JB, et al. - Researchers evaluated the ability of an alpha-defensin test to identify septic from inflammatory or crystalline arthropathy in the native knee. Researchers tested 40 native knee joint fluid specimens with cell count, fluid analysis, culture, and alpha-defensins testing. The sensitivity and specificity of the alpha-defensin test were ascertained using culture-positive fluid as the gold standard for septic arthropathy and positive crystals as the gold standard for crystalline arthropathy. This study’s findings demonstrate that alpha-defensins testing, in the form of the Synovasure prosthetic joint infections test, has a high false-positive rate when applied to identify septic and inflammatory arthritis in the native knee joint. Further study is needed to ascertain the sensitivity and specificity of the newer native joint panel. It has been considered that clinicians should be cognizant of the specific alpha-defensin test used when sampling native knee synovial fluid.