Evaluation of a new human immunodeficiency virus antigen and antibody test using light-initiated chemiluminescent assay.

Abstract

Objectives: The goal of this study is to evaluate the analytical and clinical performance of a new human immunodeficiency virus antigen and antibody (HIV Ag/Ab) test using light-initiated chemiluminescent assay (LiCA^®) and compare it with the well-established Architect^® HIV Ag/Ab combo assay in a clinical setting.

Methods: We used banked samples and national reference controls to identify the ability to detect HIV Ag/Ab and different viral subtypes. Thirteen seroconversion panels were tested to evaluate early detection of HIV. A total of 21,042 patient samples were collected to compare the diagnostic performance of LiCA^® with Architect^®. Screening-reactive results were confirmed by Western blotting and nucleic acid testing.

Results: Total imprecision was within 2.49%-6.56%. The C₅-C₉₅ interval was within -10.20%-7.67% away from C₅₀. The limit of detection for p24 antigen was <1.00 IU/mL. Using national reference panels and banked sample pools, LiCA^® successfully detected all negative and positive controls in line with the criteria, and all HIV-positive specimens containing different viral subtypes. In 13 seroconversion panels, LiCA^® detected reactive results on average 5.73 days (95% CI: 3.42-8.04) after the initial RNA test results were confirmed positive, which was 1.27 days earlier (-3.75 to 1.21) compared to Architect^®. Paired comparisons in 21,042 clinical patient samples demonstrated that LiCA^® detected HIV Ag/Ab with a slightly better performance in sensitivity (100.00% vs. 99.65%), specificity (99.85% vs. 99.81%), negative predictive value (NPV, 100.00% vs. 99.99%), and positive predictive value (PPV, 89.84% vs. 87.85%) than Architect^®. Total agreement between two assays was 99.67% with a kappa value of 0.89.

Conclusion: LiCA^® HIV Ag/Ab is a precise and highly sensitive assay for measuring HIV-1 p24 antigen and HIV-1/2 antibodies with differentiated S/Co values of Ag/Ab. The assay is appropriate for use in the clinical routine test for the early detection of HIV.