Can the Wondfo® SARS-CoV-2 IgM/IgG antibodies be used as a rapid diagnostic test?

Background: An outbreak of novel coronavirus (SARS-CoV-2) disease (COVID-19) has rapidly spread worldwide. The aim of this study was to evaluate and validate the performance of the Wondfo® lateral-flow immunochromatographic assay that detect SARS-CoV-2- IgG, IgM antibodies (Wondfo® IC), using the results obtained by the fluorescence immunoassay test as reference diagnostic. Material and methods: 97 serum specimens collected and analyzed by four independent laboratories of Sergipe/Brazil was used for validated the Wondfo® SARS-CoV-2 IgM/IgG antibodies test. The COVID-19 positive serum specimens were determined by fluorescence immunoassay technique, used as reference standard. Results: An overall of 97 serum specimens show 39 (39/97) SARS-CoV-2 IgG positive specimens, 33 (33/97) SARS-CoV-2 IgM positive specimen and 25 non-reagent specimens (25/97). However, the Wondfo® IC assay detected only 9 (9/97) IgM/IgG positive specimen and 25 (25/97) no-reagent specimen. A weak correlation was found between the outcomes of the Wondfo® IC assay and fluorescence test. The accuracy between the two tests was 32.08%. The sensitivity, specificity, positive predictive value, and negative predictive value of Wondfo® IC assay were of 11.12%, 100%, 100% and 25.27%, respectively. Moreover, no false positive sample was determinate, whereas 88.89% of false negative results were found. Conclusion: The Wondfo® IC test failed in providing a quick, valid, and reliable results and appears not to be a good alternative for clinical use in detecting pandemic coronavirus. However, if the limitations of the rapid test are known, some correction factors can be used in order to adjust the epidemiological data.