Mindray CL900i CLIA HIV Ag/Ab Combo assay: a reliable solution for highly sensitive and specific HIV screening

Abstract Background: Architect-HIV Ag/Ab combo chemiluminescence assay is globally recognized for its sensitivity but has a notable false-positive rate. Aim:To evaluate the performance of a new cost-effective screening alternative, the chemiluminescence Ag/Ab combo assay (CL-900i-HIV) from Mindray, China. Method: We selected 195 archived samples, classified based on the gold standard Inno-Lia HIVI/II-line immunoassay 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=22; positive by Architect-HIV & indeterminate by Inno-Lia-HIV). We tested all samples using the Mindray CL-900i-HIV and all positive Architect-HIV samples (n=80) were confirmed by PCR. Results: 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%). Conclusion: 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.