Yes, check the expiration dates on the test kit.
The iHealth COVID-19 Antigen Rapid Test does expire. There are expiration dates on nearly every item in the kit, but locate the expiration data on the box itself.
Update: The iHealth COVID-19 Antigen Rapid Test shelf life has increased by 3 months.
On Mar 29, 2022, the FDA granted a three-month shelf-life extension for the iHealth COVID-19 Antigen Rapid Test, which extended the shelf-life of all iHealth tests with expiration dates on or before 2022-09-29 (YYYY-MM-DD) from 6 months to 9 months. For example, if the expiration date printed on your box says 2022-05-21 (YYYY-MM-DD), the updated expiration date is 2022-08-21 (YYYY-MM-DD). We will continue to apply to FDA for shelf-life extensions every three months based on our stability studies, and the new shelf-lives for our tests will apply to tests already produced as well as future production. - iHealth Labs
For more information, visit iHealth's website here: https://ihealthlabs.com/pages/news#expiration