antigeentests

Antigen tests are diagnostic tools that detect specific proteins from a pathogen, most often viral proteins, to indicate a current infection. They are commonly referred to as rapid antigen tests and are designed for point-of-care use or self-testing, providing results in a short time.

Most respiratory virus antigen tests use a lateral flow immunoassay. A patient sample is applied to a test strip; if the target protein is present, a visible line appears, indicating a positive result. Results are typically available within 15 to 30 minutes and do not require specialized laboratory equipment.

Common specimen types include nasal swabs, nasal mid-turbinate swabs, or saliva, depending on the test. Proper collection, handling, and adherence to instructions are important for accuracy.

Advantages of antigen tests include rapid results, lower cost, and ease of use, making them suitable for on-site screening in schools, workplaces, and clinics. Limitations include generally lower sensitivity than molecular tests such as RT-PCR, particularly in individuals with low viral load or testing outside the peak infectious period. A negative result may not completely rule out infection, and false positives are possible though less common. Performance depends on factors such as viral load, timing relative to exposure or symptoms, and proper test execution.

Regulatory oversight varies by country; many authorities authorize these tests under specific conditions and publish performance characteristics. In practice, antigen test results are interpreted alongside clinical assessment and, when indicated, confirmed with molecular testing.