The Diagnostic Accuracy of SARS-CoV-2 Rapid Antibody Tests among Asymptomatic Employees Returning to Work During General Community Quarantine Period (June 1 to July 31, 2020)

Abstract

Objectives. The study was done to determine the diagnostic accuracy of rapid antibody tests (RATs) in detecting SARS-CoV-2 infection among asymptomatic employees returning to work. The study also aimed to determine the prevalence of asymptomatic RT-PCR-confirmed COVID-19 infection among these workers.

Methods. The study was a retrospective cohort of asymptomatic employees involved in the manufacturing, marketing, and sales of pharmaceutical, consumer, and animal products in the Philippines. They underwent screening for COVID-19 using both rapid antibody and RT-PCR tests as part of the return-to-work company policy from June 1 to July 31, 2020. The sensitivity and specificity of the RATs were computed using RT-PCR as the reference standard. The prevalence of RT-PCR positive COVID-19 infections among asymptomatic returning workers was also determined.

Results. Asymptomatic workers (n=5,585) were simultaneously tested for COVID-19 using RAT and RT-PCR. The sensitivity of a positive IgG and IgM was 23.9 (95% CI: 22.8 – 25.0), while the specificity was 93.3 (95% CI: 92.6 - 93.9). The prevalence of RT-PCR identified COVID-19 infection among asymptomatic workers was 4.9% (95% CI: 4.4 – 5.5).

Conclusion. The utility of RATs as a screening tool to detect asymptomatic COVID-19 individuals is limited due to its low sensitivity compared to RT-PCR.