Evaluation of the mindray CL900i CLIA HIV Ag/Ab combo assay for sensitive and specific HIV screening compared to established methods

Architect-HIV Ag/Ab combo chemiluminescence assay is globally recognized for its sensitivity but has a notable false-positive rate. In this study, we aim to evaluate the performance of a new cost-effective screening alternative, the chemiluminescence Ag/Ab combo assay (CL-900i-HIV) from Mindray, China. We selected 195 archived samples categorized according to the INNO-LIA™ HIV I/II, the gold standard confirmatory assay. These samples included true positive (n = 38; positive by Architect-HIV & INNO-LIA-HIV), true negative (n = 101; negative by Architect-HIV & INNO-LIA-HIV), false positive (n = 20; positive by Architect-HIV & negative by INNO-LIA-HIV), and indeterminate results (n = 26). We tested all samples using the Mindray CL-900i-HIV and all positive Architect-HIV samples (n = 80) were confirmed by PCR. Compared to INNO-LIA™ HIVI/II line immunoassay confirmatory assay, Mindray CL-900i-HIV demonstrated a sensitivity of 100% (95% CI 90.7-100), specificity of 100% (95% CI 97.0-100), overall percent agreement (OPA) of 100% (95% CI 97.7-100.0), and perfect agreement with the INNO-LIA confirmatory assay (κ = 1.00). Additionally, Mindray's CL-900i-HIV exhibited a significantly lower false-positive rate (8.75%) compared to Architect-HIV's (55%). Mindray CL900i demonstrated high sensitivity and very low false-positive rate, thus, has the potential to serve as an excellent, cost-effective surrogate for HIV screening, overcoming the limitations of existing automated assays.