Evaluation of the performance of a novel chemiluminescence immunoassay for cryptococcal antigen detection

This study evaluated the diagnostic performance of a chemiluminescence immunoassay (CLIA) for detecting the Cryptococcus glucuronoxylomannan (GXM) antigen and assessed its agreement with the U.S. Food and Drug Administration (FDA)-approved IMMY lateral flow assay (LFA). From June 2021 to September 2023, a total of 651 specimens (633 cerebrospinal fluid, 18 serum) collected from 208 cryptococcosis and 415 non-cryptococcosis patients (based on diagnostic criteria for cryptococcosis) were analyzed by Dynamiker GXM antigen-CLIA platform and IMMY GXM antigen-LFA platform. Among 623 participants, the CLIA method demonstrated a total percentage agreement (TPA) of 99.52% relative to LFA. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CLIA were 99.04, 100, 100, and 99.52%, respectively. Serial monitoring in patients receiving antifungal therapy showed a progressive decline in GXM antigen concentrations over time. The CLIA-based GXM assay exhibited high sensitivity and specificity for the diagnosing of cryptococcosis and showed close alignment with the FDA-approved LFA. It enables tracking antigen concentration changes during treatment, providing preliminary reference for therapeutic monitoring.

This study demonstrates that the novel chemiluminescence immunoassay (CLIA) and the conventionally used LFA have a comparable performance in the detection of glucuronoxylomannan in cerebrospinal fluid (CSF) among patients with cryptococcosis. It enables tracking antigen concentration changes during treatment, providing preliminary reference for therapeutic monitoring.