Test performance of a commercial cryptococcal antigen lateral flow assay: a retrospective and prospective study at five Canadian sites

. Inter-assay precision evaluation highlighted substantial variability in the FungiXpert CrAg LFA serum testing. These findings suggest similar performance of the FungiXpert CrAg LFA on CSF samples, but lower sensitivity on serum samples and greater lot-to-lot variability compared to IMMY CrAg LFA that should be considered in clinical implementation decision-making. In this Canadian multicenter study, the FungiXpert CrAg LFA demonstrated similar performance on CSF samples but lower sensitivity on serum samples compared to the IMMY CrAg LFA.IMPORTANCEThis multicenter Canadian evaluation provides the first North American performance data for the Health Canada-licensed FungiXpert cryptococcal antigen lateral flow assay. While performance on cerebrospinal fluid was comparable to the reference IMMY assay, reduced sensitivity for low-titer serum samples and greater inter-assay variability highlight important considerations for clinical implementation and assay selection.