Rapid Antigen Tests (RATs) are designed to quickly detect specific viral proteins, called antigens, in a sample taken from the body. These tests are a common way to screen for respiratory illnesses.
Combination RATs, as highlighted by the reference, offer the ability to test a nasal swab, saliva, or oral fluid sample for multiple viruses that cause respiratory disease simultaneously. This includes testing for viruses like COVID-19, Influenza A, and Influenza B using a single test device.
The Science Behind RATs
At their core, RATs utilize a process called lateral flow immunoassay. Here's a simplified breakdown:
- Sample Collection: You collect a sample, typically using a nasal swab, or in the case of combination tests, potentially a saliva or oral fluid sample as per the reference.
- Sample Processing: The collected sample is usually mixed with a buffer solution. This solution helps extract the viral antigens and prepares them for the test.
- Applying the Sample: The processed sample is then placed onto a designated spot on the test cassette.
- Lateral Flow: The liquid sample flows across a strip of material inside the cassette. This strip contains specific antibodies designed to bind to the antigens of the target viruses (e.g., SARS-CoV-2, Influenza A, Influenza B).
- Result Display: As the sample flows, if the target viral antigens are present, they bind to the antibodies on the strip. This binding causes a visible line to appear in specific areas on the test cassette.
How to Interpret the Results
RATs typically have one or two lines that appear:
- Control Line (C): This line must appear for the test to be valid, indicating the test worked correctly.
- Test Line(s) (T): If a line appears in the test region (T), it indicates the presence of antigens from the target virus(es). For combination tests, there might be separate test lines for different viruses (e.g., one for COVID-19, one for Flu A, one for Flu B).
A positive result (Control line + Test line(s)) suggests the presence of the virus. A negative result (only Control line) suggests the target viruses were not detected at that time. An invalid test (no Control line) means the test didn't run correctly.
Practical Use of Combination RATs
Combination RATs offer convenience by testing for multiple common respiratory viruses at once.
| Feature | Description |
|---|---|
| Sample Type | Nasal swab, saliva, or oral fluid sample (based on test type) |
| Detection | Specific viral antigens (proteins) |
| Target Viruses | Multiple respiratory viruses (e.g., COVID-19, Influenza A & B) |
| Result Time | Typically 10-20 minutes |
These tests are designed for self-testing or use by a trained individual and provide rapid results outside of a laboratory setting.
