Many individuals wonder about the reliability of at-home COVID-19 tests once their printed expiration date has passed. Understanding what these dates signify and how they impact test performance is important for accurate results and informed health decisions.
Why COVID Tests Have Expiration Dates
COVID-19 tests, like many medical products, carry expiration dates determined through rigorous scientific evaluation. Manufacturers conduct stability testing to ensure the test components maintain their intended performance over time. This process assesses how long the test remains effective under various environmental conditions, including temperature and humidity. The expiration date signifies the period during which the manufacturer guarantees the product’s quality, safety, and accuracy. This date is established based on data submitted to regulatory bodies, such as the U.S. Food and Drug Administration (FDA), which authorizes the shelf life of these diagnostic tools.
What Happens When a Test Expires?
When a COVID-19 test reaches its expiration date, the chemical components within the kit can begin to degrade. Reagents, such as the antibodies on the test strip, are designed to detect specific viral proteins. These antibodies can lose their ability to bind effectively to the virus over time. The buffer solution, another part of the test, can also degrade or evaporate, leading to insufficient liquid for the chemical reaction. Environmental factors like temperature fluctuations can accelerate this breakdown, compromising the test’s ability to accurately identify the presence of the SARS-CoV-2 virus.
Risks of Using an Expired Test
Using an expired COVID-19 test risks inaccurate results. The most common concern is a false negative, where the test indicates no infection even when the virus is present. This occurs because degraded components may fail to detect viral proteins, leading to a misleading “negative” reading. While less common, a false positive is generally unlikely if the chemicals have broken down. An unreliable test result could lead an infected individual to unknowingly spread the virus, delay seeking medical care, or isolate unnecessarily based on an incorrect positive result.
What to Do If Your Test is Expired
If your COVID-19 test kit has passed its printed expiration date, dispose of it and obtain a new, unexpired test. Unused and expired tests can be disposed of in regular household trash. Before discarding, check if the FDA has extended the expiration date for your specific test brand. Many manufacturers have submitted additional data allowing for extended shelf lives, sometimes by several months. You can verify these extended dates by checking the FDA’s website, often by searching for your test’s manufacturer and lot number.