Omicron's swift rise in the US has led to a serious shortage of a pandemic necessity: at-home COVID-19 tests. And as people scramble to find some at their local pharmacies or online retailers, scammers have stepped up to the plate to sell their own unauthorized versions. In a blog post shared on January 4, the Federal Trade Commission (FTC) warned that these fake at-home tests aren't only a waste of money, but they also "[increase] your risk of unknowingly spreading COVID-19 or not getting the appropriate treatment." The Food and Drug Administration (FDA) also sounded the alarm about fraudulent COVID-19 tests, along with other unauthorized products, including treatments, medical devices, or vaccines. So how can you ensure the COVID test you have in your online shopping cart is a legitimate diagnostic tool and not an impostor? Here are four ways to confirm your at-home test's validity before making a purchase. Make sure your test is authorized by the FDA You'll want to check that the test is authorized for emergency use by the FDA—no exceptions. That specific wording—"authorized" rather than "approved"—is important, Mara Aspinall, a professor of biomedical diagnostics at Arizona State University, tells Health. That's because COVID tests have only been given emergency use authorizations (EUAs), and if someone is trying to sell you a test that is "FDA-approved," it's a red flag. "It is critical that people only use tests that are authorized in the United States," Aspinall says. The FDA has two separate lists of tests given an EUA: One shows all the authorized antigen diagnostic tests, which are the ones most commonly used as at-home COVID tests. The other list shows all authorized molecular diagnostic tests, which are most commonly the polymerase chain reaction (PCR) tests administered by professionals (only a select few are authorized for home use). The following antigen diagnostic tests are authorized for at-home use: BinaxNOW COVID-19 Ag Card Home Test BinaxNOW COVID-19 Antigen Self Test BinaxNOW COVID-19 Ag Card 2 Home Test COVID-19 At-Home Test by SD Biosensor, Inc. CLINITEST Rapid COVID-19 Antigen Self-Test iHealth COVID-19 Antigen Rapid Test CareStart COVID-19 Antigen Home Test BD Veritor At-Home COVID-19 Test SCoV-2 Ag Detect Rapid Self-Test by InBios International, Inc. InteliSwab COVID-19 Rapid Test Celltrion DiaTrust COVID-19 Ag Home Test QuickVue At-Home OTC COVID-19 Test Flowflex COVID-19 Antigen Home Test InteliSwab COVID-19 Rapid Test Rx QuickVue At-Home COVID-19 Test Ellume COVID-19 Home Test The following molecular diagnostic tests are authorized for at-home use: Detect Covid-19 Test Lucira CHECK-IT COVID-19 Test Kit Cue COVID-19 Test for Home and Over The Counter Use Lucira COVID-19 All-In-One Test Kit Coronavirus Home Tests: How They Work, What They Cost, and How Accurate They Are Pay for your test with a credit card There are two ways scammers are preying on shoppers looking for COVID-19 at-home tests right now, Aspinall says: Some are taking orders for tests and sending nothing to the customers who have already paid them. Others are sending fake, faulty, or unauthorized tests to customers. One way you can protect yourself while online shopping for tests is by paying for them with a credit card. "If you're charged for an order you never got, or for a product that's not as advertised, contact your credit card company and dispute the charge," the FTC says. Buy from reputable retailers and websites Treat your at-home COVID test like you would your prescriptions—that means buy them at the stores you use frequently, if you can. Aspinall suggests big-name stores—Walmart, Target, CVS, Amazon—are the safest options. This also ensures that your tests will still be within the expiration date (at-home tests have a shorter shelf life—some can expire in a few months). That also means you should be extremely skeptical of anyone selling at-home COVID tests on the street and avoid them, says Aspinall. If you do end up purchasing tests from an unfamiliar website, you should do your homework before clicking the "buy" button. "Compare online reviews from a wide variety of websites, [and] think about the source of the review," the FTC says. In addition to checking out reviews, it might be worth Googling the name of the website next to words like "scam" and "complaint." This might pull up warnings from other online shoppers that can help inform your decision. And if you were considering buying any at-home COVID tests from Facebook or Instagram marketplaces, you should probably reconsider. "In general, avoid buying off social media platforms," says Aspinall.