Rapid Antigen Tests: Accurate or Antiquated?

January 7, 2023

The threat of emerging Omicron variants has underscored the need to examine our current testing tools, specifically rapid antigen tests (RAT).

At-home over-the-counter (OTC) rapid antigen tests are designed to detect proteins called antigens from SARS-CoV-2, the virus that causes COVID-19. The tests are less likely to detect the virus than molecular tests, such as polymerase chain reaction (PCR) tests and other nucleic acid amplification tests (NAATs), which detect genetic material from the virus.

Changes in a viral genome can result in changes to viral proteins and can impact the accuracy and performance of an antigen test. In response to rapidly mutating variants, the FDA has been collaborating with the National Institutes of Health's (NIH) RADx program to study the performance of antigen tests with patient samples.

In an extensive study that examined rapid antigen test performance, researcher partners at UMass Chan Medical School found that at-home OTC antigen tests are more likely to detect COVID-19 within the first week of infection when an asymptomatic individual tests three times at 48-hour intervals, and a symptomatic person tests twice. The research is documented in medRxiv, an online preprint platform, and has yet to be peer-reviewed.

These findings affirm advice provided by the FDA for repeat testing, also called serial testing. This means people who receive a negative test result should use multiple tests to reduce the risk of overlooking an infection (false negative result) and to help prevent people from unknowingly spreading the SARS-CoV-2 virus/COVID-19 to others. For more information, read FDA Safety Communication.

The mutations in the viral genome of current Omicron variants call into question if rapid antigen testing is a reliable option in 2023. RT–PCR remains the gold standard of testing due to its high sensitivity and specificity.

Connect with our Home Test Kit Team to order at-home rapid antigen tests in bulk at htksupport@flowhealth.com or text (323) 652-4696.

For greater accuracy, schedule a PCR test at any of our Patient Service Centers.

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