CHIT1 and sarcoidosis: A limitation of this study concerns the size of the population, since it was a monocentric study in a center devoted to rare diseases and with a specific case mix; however, the message from this study is that the non-invasive and rapid CHIT1 test can represent a specific and sensitive diagnostic tool to discriminate active sarcoidosis patients in the FUO group, contributing in a decisive way to finalizing the diagnostic process.