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

UNLABELLED: 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.

IMPORTANCE: 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.