Evaluation of Rapid Antigen Testing (Panbio™ COVID-19 Ag Rapid Test Device) for COVID-19 Diagnosis in a Tertiary Hospital

Abstract

Background. The Panbio™ COVID-19 Ag Rapid Test is a Food and Drug Administration (FDA)-approved point-of-care test (POCT) used for SARS-CoV-2 detection which has met minimum sensitivity and specificity requirements by the World Health Organization (WHO).

Objective. The study aimed to compare the clinical performance of a commercial lateral flow assay (LFA) to reverse transcriptase polymerase reaction (RT-PCR) in SARS-CoV-2 infection diagnosis

Methodology. Clinical data and simultaneous LFA and RT-PCR samples collected from June 2021 to June 2022 were obtained to analyze the diagnostic accuracy of LFA compared to RT-PCR.

Results. A total of 265 samples was obtained. 34.45% of RT-PCR positive samples were reliably detected by LFA. COVID-19 was reliably ruled out by LFA in 99.32% RT-PCR negative samples. LFA sensitivity among symptomatic patients with ≤7 days of illness was 51.61%, slightly higher than those with >7 days of illness (18.92%), and significantly higher than asymptomatic patients (16.67%). Asymptomatic subjects have a varied range of Ct-values, indicating different stages of infection or viral loads. Individuals with symptoms for more than 7 days have higher Ct-values, suggesting they are in later stages of infection or have lower viral loads. The probability of a positive LFA result decreases significantly when the Ct-value is beyond 28-30.

Conclusion. The LFA evaluated in this study did not show significant sensitivity and specificity during the early disease course wherein viral loads are suggestively high. However, its utility to accurately rule out COVID-19 is quite reliable in subjects with symptoms that are >7 days since Ct-values are suggestively beyond 28-30 which implies a significantly decreased probability of a positive LFA result.