At-home COVID tests, also known as rapid antigen tests, work by detecting specific proteins (antigens) of the SARS-CoV-2 virus directly from your nasal sample, providing results quickly without needing to be sent to a lab.
Here's a breakdown of how they function:
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Sample Collection: You collect a sample, usually by swabbing your nostrils.
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Antigen Detection: The swab is then mixed with a solution that releases viral proteins (if present). This mixture is applied to a test strip containing antibodies that are specifically designed to bind to SARS-CoV-2 antigens.
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Antibody Binding: If the virus is present in your sample, the antigens will bind to these antibodies on the test strip.
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Visual Result: This binding triggers a visible color change on the test strip, indicating a positive result. A control line is also present to confirm the test is working correctly. If the control line doesn't appear, the test is invalid.
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Rapid Results: The reaction and color change occur relatively quickly, providing results within approximately 15 minutes. Because they don't require lab processing, at-home tests offer convenience and speed.
Key Components:
- Antibodies: Specific proteins engineered to recognize and bind to SARS-CoV-2 antigens.
- Test Strip: A paper-like strip containing the antibodies and chemicals needed to produce a visible signal.
- Control Line: A line that appears regardless of the presence of the virus, confirming the test is functioning properly.
- Reaction Chamber: Where the sample mixes with the test solution and interacts with the test strip.
In essence, at-home COVID tests function like a pregnancy test, where a colored line appears if the target substance (in this case, viral antigens) is present. Because the tests look for proteins, and not the virus's genetic material, the results can be read in minutes, but they can be less sensitive than PCR tests, which are processed in a laboratory.
