Table of Contents

1. Introduction
2. Antigen Test Accuracy
3. Factors Impacting Accuracy
4. Comparative Performance with Other Tests
5. Immuno Company Solutions
6. References

Introduction

COVID-19 antigen tests, known for their rapid results, have become significant tools in managing the pandemic. Understanding their accuracy is essential for making informed decisions regarding public health measures and individual actions.

Antigen Test Accuracy

The accuracy of COVID-19 antigen tests is measured primarily in terms of sensitivity and specificity. Sensitivity, the ability to correctly identify positive cases, typically ranges from 50% to 80%, as reported in various studies (Paltiel et al., 2020). Specificity, which is the ability to correctly identify negative cases, is generally higher, often exceeding 95%.

Factors Impacting Accuracy

Several factors can affect the accuracy of antigen tests:

• Viral Load: Higher viral loads usually result in higher sensitivity. Antigen tests are more likely to detect the virus in symptomatic individuals or those in the early stages of infection.
• Timing of the Test: Conducting tests too early or late in the infection cycle can result in false negatives due to low viral load.
• Sample Collection: Proper technique in sample collection substantially affects test accuracy. Inadequate sample collection can lead to incorrect results.
• Test Brand and Quality: Different test kits vary in performance. WHO-approved tests tend to have better validated accuracy metrics.

Comparative Performance with Other Tests

When compared to RT-PCR tests, antigen tests exhibit lower sensitivity but similar specificity. RT-PCR tests, considered the gold standard, generally show sensitivity and specificity rates exceeding 95%. However, they require longer processing times and complex laboratory setups.

Immuno Company Solutions

Companies like Abbott, Quidel, and Roche have developed antigen testing solutions that offer high specificities and competitively high sensitivities:

• Abbott BinaxNOW™: Offers an approximate 84.6% sensitivity and 98.5% specificity.
• Quidel Sofia® SARS Antigen FIA: Shows sensitivity of 80% and specificity of 99%.
• Roche SARS-CoV-2 Rapid Antigen Test: Demonstrates approximately 76.6% sensitivity and 99.3% specificity.

References

1. Paltiel, A. D., Zheng, A., & Walensky, R. P. (2020). Assessment of SARS-CoV-2 Screening Strategies to Permit the Safe Reopening of College Campuses in the United States. JAMA Network Open, 3(7), e2016818.
2. World Health Organization. (2020). Antigen-detection in the diagnosis of SARS-CoV-2 infection using rapid immunoassays. Interim Guidance.
3. Parker, C. et al. (2021). Comparative Review of Antigen Detection Test Performance for COVID-19. Journal of Clinical Virology, 142.