Effectiveness of Rapid Antigen vs Reverse Transcription Polymerase Chain Reaction Tests in Ruling out SARS-CoV-2 Infection

Concept of COVID-19 or 2019-ncov coronavirus
Researchers conducted a study that compared the effectiveness of antigen-based rapid diagnostic testing vs reverse transcription quantitative polymerase chain reaction testing in ruling out SARS-CoV-2 infection in symptomatic patients.

Among patients with COVID-19-related symptoms, results of a retrospective analysis found that point-of-care, antigen-based rapid diagnostic tests (RDTs) were more effective than reverse transcription quantitative polymerase chain reaction (RT-qPCR) tests at ruling out SARS-CoV-2 infection. These findings were published in Cureus.

During the COVID-19 pandemic, RT-qPCR has been the gold standard for diagnosing SARS-CoV-2 infection. However, access to RT-qPCR tests may be decreased in regions experiencing increased SARS-CoV-2 infection rates. To assess whether RDTs have clinical utility or are a viable alternative when access to RT-qPCR tests is decreased, the researchers retrospectively reviewed data on patients hospitalized in India. The sensitivity and specificity of the testing methods were compared.

Among a total of 321 patients included in the study, the mean age was 29.4 ± 10.11 years, 81% were men, and 41% had 1 or more COVID-19-like symptoms.

Overall, there were 255 true negative, 30 true positive, 26 false negative, and 7 false positive test results among the included patients, corresponding with a SARS-CoV-2 infection diagnosis rate of 17.6%. After stratification by RDT and RT-qPCR assays, the researchers noted a moderate agreement between the 2 tests (k, 0.57; P =.000).

In regard to RDTs, the sensitivity was 53.6% (95% CI, 39.7-67.0), specificity was 97.3% (95% CI, 94.6-98.9), positive predictive value was 81.1% (95% CI, 64.8-92.0), and negative predictive value was 90.7% (95% CI, 86.7-93.9).

The researchers compared symptomatic vs asymptomatic patients  and found that the RDTs had increases in both sensitivity (61.0% vs 33.3%) and positive predictive value (83.3% vs 71.4%), as well as  decreases in both specificity (94.4% vs 98.8%) and negative predictive value (84.2% vs 94.4%) among those who were symptomatic. This discrepancy indicated that the RDTs were more effective at ruling out SARS-CoV-2 infection compared with RT-qPCR, which was more effective at diagnosing infection.

This study was limited by its lack of determining the sufficient sample size for assessing the power of the 2 diagnostic tests.

The researchers concluded that RDTs are an important tool for managing the ongoing COVID-19 pandemic, specifically for ruling out SARS-CoV-2 infection among undiagnosed patients who exhibit COVID-19-like symptoms.


Pandey AK, Mohanty A, Hada V, et al. Comparison of the rapid antigen testing method with RT-qPCR for the diagnosis of COVID-19. Cureus. 2021;13(8):e17405. doi:10.7759/cureus.17405