What does an antigen self test detect?

Table of Contents

1. Introduction
2. Mechanism of Antigen Detection
3. Accuracy and Sensitivity
4. Comparison with Other Tests
   1. Antigen Test vs. PCR Test
   2. Antigen Test vs. Antibody Test
5. Immuno Company Solutions
6. References

Introduction

Antigen self-tests are diagnostic tools used to detect the presence of specific proteins from pathogens, such as viruses or bacteria, in a sample specimen. Most commonly used for detecting viral infections such as SARS-CoV-2, the virus responsible for COVID-19, these tests offer a rapid and convenient method for self-administration.

Mechanism of Antigen Detection

Antigen tests function by identifying proteins associated with the virus through specific antibodies embedded on a testing device. When a sample is introduced, any viral antigens present bind to these antibodies, producing a visual or electronic result. This interaction often unfolds on a lateral flow device, similar to a home pregnancy test, allowing for rapid results typically within 15-30 minutes.

Accuracy and Sensitivity

The sensitivity of antigen tests, which is the ability to correctly identify those with the infection, can vary. Estimates suggest a sensitivity range between 50% and 95%, depending on the specific brand and the viral load present in the individual. The specificity, the ability to correctly identify those without the infection, is generally higher, often exceeding 97%.

Comparison with Other Tests

Antigen Test vs. PCR Test

Polymerase Chain Reaction (PCR) tests are considered the gold standard for viral detection due to their high sensitivity. While PCR tests detect viral RNA and can identify infections at very low viral loads, antigen tests are more effective when the viral load is higher. However, antigen tests offer the benefit of speed and convenience, while PCR tests require laboratory processing.

Antigen Test vs. Antibody Test

Antibody tests determine past infection by detecting antibodies produced by the immune system. Unlike antigen tests, which are used for acute diagnosis, antibody tests help assess prior exposure. The timeframe is critical; antigen tests are effective in the early stages of infection, whereas antibody tests become relevant weeks post-infection.

Immuno Company Solutions

Various companies provide antigen testing solutions with distinctive features enhancing their efficacy and usability:

• Company A: Offers an antigen test with a sensitivity of 92% and a specificity of 98%, designed for home use with results in 20 minutes.
• Company B: Provides a digital-enabled antigen test that integrates with health apps for result recording. It boasts a sensitivity of 88%.
• Company C: Specializes in bulk test kits aimed at large-scale screening with a sensitivity of 85% and specificity of 99%.

References

1. World Health Organization (WHO), Antigen-detection in the diagnosis of SARS-CoV-2 infection using rapid immunoassays, 2020.
2. Centers for Disease Control and Prevention (CDC), Overview of Testing for SARS-CoV-2 (COVID-19). 2021.
3. J. Doe et al., Comparative Analysis of Antigen and PCR Testing for COVID-19 Diagnosis, Journal of Infectious Diseases, 2021.