Why Your At-Home COVID Test May Be Less Effective Now

Testing is one of the most important parts of our response to the pandemic. According to The Scientist, testing not only helps to determine the efficacy of a given vaccine, but also plays a part in keeping people safe and enabling us to return to school, work, or even travel. According to the Centers for Disease Control and Prevention (CDC), there are two main kinds of COVID-19 tests. Nucleic acid amplification tests (NAATs), such as PCRs, are viewed as more reliable and are typically analyzed in a lab. On the other hand, antigen tests, like at-home tests, are much more rapid and convenient. However, the CDC warns that at-home tests are preliminary results and do not guarantee that you are safe or rule out infection. 

In late 2020 the United States Food and Drug Administration (FDA) approved the first at-home rapid COVID-19 diagnostic test. The test — brand name Lucira COVID-19 All-In-One Test Kit — allows people to use swabbed nasal samples to test themselves for infection. Results appear on a colored display in under 30 minutes. Today, there are over 20 kinds of FDA-approved at-home COVID-19 diagnostic tests, which are available over the counter. Despite the convenience, at-home tests are "less reliable than NAATs, especially for people who do not have symptoms" says the CDC. Those concerns are being echoed today, as questions about the efficacy of at-home tests with the Omicron variant have begun to surface.

The Omicron variant was identified in November 2021 and caused a surge in COVID-19 cases in the United States through early 2022, says the Centers for Disease Control and Prevention (CDC). The United States Food and Drug Administration (FDA) released a statement before the end of 2021 saying that antigen tests "detect the omicron variant but may have reduced sensitivity." In 2022, research produced some interesting results.

By May 2022 outlets warned that the at-home tests could be less effective in detecting the new variants of COVID-19 (per Harvard School of Public Health). For example, a 2022 study published in the Journal of Clinical Microbiology found that while several rapid antigen tests (for use at home) were successful at detecting the Omicron variant, they were less effective at detecting the Delta variant. However, a more recent 2022 study published in the British Medical Journal that compared the results of on-site PCR tests to at-home rapid antigen tests found that the at-home tests became less sensitive during the period that Omicron emerged as the most prominent variant. One test — brand name Clinitest — showed a statistically significant change in detection sensitivity (per U.S. News & World Report). Notably, the researchers studied the efficacy of at-home tests when taken in an unsupervised environment. According to the CDC, it is extremely important to follow the full set of manufacturer instructions on an at-home test because failure to do so can produce invalid results.