Evaluation of the GeneTex U-OK SARS-CoV-2 Neutralizing Antibody Detection Assay: Comparison With GenScript cPass and...

The detection of neutralizing antibodies (NAbs) is crucial for evaluating immune protection against viral infections. This study assessed two ELISA-based surrogate virus neutralization tests (sVNTs): the novel GeneTex U-OK SARS-CoV-2 Neutralizing Antibody Detection ELISA kit and the FDA-authorized GenScript cPass SARS-CoV-2 Neutralization Antibody Detection kit. The GeneTex U-OK kit contains recombinant spike proteins from the wild-type strain and Omicron subvariants BA.1, BA.2, and BA.4/BA.5. A total of 115 serum samples were analyzed, including 75 from SARS-CoV-2 unvaccinated individuals and 40 from vaccinated individuals. No participant had evidence of prior SARS-CoV-2 infection, as confirmed by negative anti-nucleocapsid antibody tests. Compared with the GenScript cPass kit, the GeneTex U-OK kit demonstrated 100% positive agreement (95% CI: 90.4-100.0%) and 100% negative agreement (95% CI: 95.4-100.0%) in detecting NAbs against the wild-type strain, corresponding to 100% sensitivity and 100% specificity. When compared with viral neutralization assays, it achieved 100% concordance for Omicron BA.1, BA.2, and BA.4/BA.5 subvariants, with correlation coefficients (R) of 0.85, 0.98, and 0.46, respectively. These findings highlight the accuracy and reliability of the GeneTex U-OK kit, indicating its potential as a valuable tool for monitoring vaccine effectiveness and identifying individuals with protective NAbs against vaccinated individuals, including Omicron variants.