Checking the expiration date on an at-home COVID-19 test is necessary before use. Like any diagnostic tool, these tests rely on chemical reagents, specifically antibodies, designed to capture the SARS-CoV-2 viral protein, or antigen. Over time, these delicate biological components naturally degrade. This degradation compromises the test’s ability to accurately detect the virus, increasing the risk of a false negative result.
Locating the Printed Expiration Date
The expiration date is typically printed on the outer cardboard box, which is the primary packaging for the kit. This date represents the manufacturer’s initial estimate of the test’s stability. The date is often stamped or printed in a small, sometimes faint, location near the lot number or batch code, requiring a careful inspection of all sides of the box. While a date may also appear on the foil pouch containing the test cassette, the date on the external box is the most common reference point and should be used for initial verification.
Decoding Date Formats and Symbols
Once the date is located, you must correctly interpret the format, which varies between manufacturers. The expiration date is frequently presented as YYYY-MM-DD or MM/YY, usually indicating the last day of the month shown. To distinguish the expiration date from other information, look for specific symbols printed nearby, such as a small hourglass or the abbreviation “EXP.” This must be differentiated from the “Manufacturing Date,” which indicates when the test was produced. The manufacturing date is often marked with a symbol resembling a small factory or the abbreviation “MAN.”
Checking for Authorized Expiration Extensions
A unique aspect of at-home COVID-19 tests is that their shelf life may be officially extended beyond the date printed on the box. This occurs because manufacturers continue to conduct stability studies after the initial authorization, submitting new data to the regulatory body. If these studies show the test reagents remain stable and accurate for a longer period, the regulatory body can authorize an extended expiration date. This extension is a formal change based on scientific evidence.
Finding the Extended Date
To determine if your test kit has an extended shelf life, you must check the official product list maintained by the Food and Drug Administration (FDA) or the manufacturer’s website. This process requires finding the Lot Number, or batch code, which is a unique identifier printed on the test box near the original expiration date. You will then match this specific Lot Number to the authorized extension list to see the new, verified expiration date. If your Lot Number appears on the list, use the extended date, even if it is months or over a year past the date printed on the box.
What to Do If Your Test Is Expired
If your test kit’s printed expiration date has passed and its Lot Number is not on an authorized extension registry, the test is truly expired and should not be used. The reagents inside the test may have degraded, increasing the likelihood of a false negative result. An expired test cannot provide a reliable result, so you should obtain a replacement kit.
Disposal of Expired Kits
When disposing of an expired, unused kit, you can generally place the entire contents into your regular household trash, as they do not qualify as regulated medical waste. For used tests, which may contain biological material, it is best practice to seal all components in a small plastic bag before placing them in the trash.