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Comparison of the Rapid Antigen Testing Method With RT-qPCR for the Diagnosis of COVID-19
Ashok Kumar Pandey1, Aroop Mohanty2, Vivek Hada2
1Virology, Indian Council of Medical Research-Regional Medical Research Centre, Gorakhpur, IND.
Insights
Rapid antigen diagnostic tests (RDTs) show lower sensitivity but high specificity for COVID-19 detection. RDTs are valuable screening tools, especially for symptomatic individuals, aiding in disease containment.
Area of Science:
- Clinical diagnostics
- Infectious disease epidemiology
- Public health
Background:
- The COVID-19 pandemic necessitated widespread testing, straining resources for quantitative reverse transcription polymerase chain reaction (RT-qPCR) kits.
- Point-of-care rapid antigen-based tests (RDTs) were developed to address the increasing demand for accessible diagnostic solutions.
- Evaluating the performance of RDTs against the gold standard RT-qPCR is crucial for their effective implementation.
Purpose of the Study:
- To compare the diagnostic performance of a rapid chromatographic antigen test (index test) against RT-qPCR (gold standard).
- To assess the sensitivity and specificity of RDTs for detecting SARS-CoV-2 infection.
Main Methods:
- Retrospective analysis conducted at a tertiary care hospital in Eastern Uttar Pradesh, India.
- Paired patient samples were analyzed using both antigen-based rapid diagnostic testing (RDT) and RT-qPCR.
- Sensitivity and specificity of the RDT were calculated to evaluate its diagnostic accuracy.
Main Results:
- The overall sensitivity of the RDT was 53.6% (95% CI: 39.7-67.0), and specificity was 97.35% (95% CI: 94.6-98.9).
- In symptomatic individuals, the sensitivity of the RDT was higher, recorded at 61.0% (95% CI: 44.5-75.8).
- Higher test positivity rates for RDT were observed at a cycle threshold (Ct) value ≤20, indicating higher viral load.
Conclusions:
- Rapid antigen diagnostic tests can serve as a valuable screening tool to identify potential COVID-19 infections, particularly in symptomatic patients.
- The high specificity of RDTs makes them useful for ruling in infection, while their performance is better in individuals with higher viral loads.
- RDTs are an important component of public healthcare strategies for the containment of COVID-19.
Background:
Coronavirus disease 2019 (COVID-19) has till now affected about 110 million people globally. It has not spared any country and has led to 24 lakh deaths. As a result, the testing had to be increased manifold leading to depletion in the number of the quantitative reverse transcription polymerase chain reaction (RT-qPCR) kits. Point-of-care rapid antigen-based tests were developed in order to meet the increasing demands. The objective of this study was to compare the performance of a rapid chromatographic test (index test) with a gold standard test (RT-qPCR).
Methods:
A retrospective analysis was done at a tertiary care teaching hospital in Eastern Uttar Pradesh, India. Paired samples were taken from all patients reporting to the clinic for antigen-based rapid diagnostic testing (RDT) and RT-qPCR. The sensitivity and specificity were calculated to evaluate the performance of the RDT.
Results:
The overall sensitivity and specificity of the RDT were observed to be 53.6% (39.7-67.0) and 97.35% (94.6-98.9), respectively. In symptomatic individuals, the sensitivity was higher 61.0% (44.5-75.8). The test positivity rates of RDT were found to be higher at a cycle threshold value ≤20.
Conclusion:
RDT can be used as a screening test to rule in the infection especially in symptomatic patients who are more prone to spread the disease. It is an important weapon in the armamentarium of public healthcare for the containment of COVID-19.
