Point-Of-Care clinical evaluation of the Clungene^® SARS-CoV-2 virus IgG/IgM 15-minute rapid test cassette with the Cobas^® Roche RT-PCR platform in patients with or without Covid-19

Background: Coronavirus disease 2019 (Covid-19) remains a pandemic with multiple challenges to confirm patient infectivity: lack of sufficient tests, accurate results, validated quality, and timeliness of results. We hypothesize that a rapid 15-minute Point-Of-Care serological test to evaluate past infection complements diagnostic testing for Covid-19 and significantly enhances testing availability.

Method: A three arm observational study at Sharp Healthcare, San Diego, California was conducted using the Clungene^® lateral flow immunoassay (LFI) and compared with the Cobas^® Roche real-time polymerase chain reaction (RT-PCR) results. Arm 1: Thirty-five (35) subjects with confirmed Covid-19 using RT-PCR were tested twice: prior to 14 days following symptom onset and once between 12 and 70 days. Arm 2: Thirty (30) subjects with confirmed Covid-19 using RT-PCR were tested 12-70 days post symptom onset. Arm 3: Thirty (30) subjects with a negative RT-PCR for Covid-19 were tested 1–10 days following the RT-PCR test date.

Results: Specificity of confirmed negative Covid-19 by RT-PCR was 100% (95% CI, 88.4%–100.0%); meaning there was 100% negative positive agreement between the RT-PCR and the Clungene^® serological test results. Covid-19 subjects tested prior to day 7 of symptom onset were antibody negative. In subjects 7–12 days following symptom onset with a confirmed positive Covid-19 by RT-PCR, the combined sensitivity of IgM and IgG was 58.6% (95% CI, 38.9%–76.5%). In subjects 13–70 days following symptom onset with a confirmed positive Covid-19 by RT-PCR, the combined sensitivity of IgM and IgG was 90.5% (95% CI, 80.4%–96.4%).

Conclusion: The Clungene^® lateral flow immunoassay (LFI) is a useful tool to confirm individuals with an adaptive immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) indicating past infection. Providing Point-Of-Care results within 15 minutes without any laboratory instrumentation or specialized software has an added value of increasing test availability to patients who have been symptomatic for more than 1 week to confirm past infection. Performance characteristics are optimal after 13 days with a sensitivity and specificity of 90% and 100%, respectively.

Statement of novelty: Formal controlled clinical studies of Covid-19 antibody tests have been limited. This study demonstrates the utility of the 15 minute rapid Clungene^® test and the potential for expanded use where Covid-19 RT-PCR testing and vaccination is limited.