With Christmas just days away, there has been a huge demand for COVID-19 tests including hard-to-find at-home kits across America. With the cases of COVID-19 rising and the more contagious omicron variant threatening the nation, people want to play it safe and get tested, but the lack of testing equipment is challenging their efforts.

Long lines and bumper-to-bumper traffic await those trying to get tested at designated sites. According to The Wall Street Journal, waiting times for COVID-19 tests are growing in parts of the U.S. as the omicron variant proves to be a formidable foe. Websites for CVS Health Corp. and Walgreens Boots Alliance Inc. show that some parts of the country won’t have testing appointments available until later this week.

Experts say you should be tested at least three days before attending a gathering, but be open to more options, says the TODAY Show. For example, rapid at-home tests can provide an excellent choice for COVID-19 testing but even these kits are becoming as scarce.

At-home tests allow you to check your COVID-19 status, according to Yahoo Life. These rapid tests are available at pharmacies, large retailers and even in some grocery stores but experts say they are flying off the shelves as the holidays approach. A quick check of the popular BinaxNOW test kit showed that it is currently unavailable at Walmart, CVS, and Sam’s Club.

But experts say if you are lucky enough to find kits, stock up.

“It makes sense to have a kit on hand so it’s there when you need it,” said Dr. Amesh A. Adalja, a leading infectious disease expert at Johns Hopkins Center for Health Security.

Dr. Sanjay Gupta, CNN’s chief medical correspondent, said that at-home COVID-19 tests are “one of the best tools we have” to stay safe during the pandemic. Gupta points out that even fully vaccinated people may carry the virus so taking a rapid antigen test can tell you if you are contagious.

Antigen tests resemble pregnancy tests, say Yale Medicine experts. They work by detecting pieces of protein from the SARS-CoV-2 virus, the virus that causes COVID-19. After a sample specimen is obtained from the nose, or sometimes the throat, it is placed on a test strip or cartridge that’s been treated with a reagent. A colored line will indicate the results.

The results should appear within 15 minutes, and while these rapid tests can give both false negative and false positive readings, they can identify about 98% of cases. If you do test positive, quarantine until you are able to take the more reliable PCR test, says The New York Times.  If your rapid test shows a negative result, and you are vaccinated, you are probably okay to attend holiday events.

To get the most bang for your buck, take the test after you think you have been exposed to the virus, and before you may be spending time with people who are elderly or have underlying medical issues. If you are attending more than one gathering this weekend, save your rapid testing for the events that will have the most vulnerable people present. The tests cost between $15 and $40 right now.

Thankfully, the Food and Drug Administration (FDA) approved three more over-the-counter rapid tests for people over the age of 14 years, so the availability of these powerful testing tools should improve in the  months to come.

According to the TODAY Show, it’s best to keep checking websites for COVID-19 test availability. Search online through health departments and pharmacies in your area. Any test is better than none, say experts, however the FDA revealed that certain at-home tests are unable to detect omicron. These include Applied DNA Sciences, Meridian Bioscience and Tide Laboratories, according to the TODAY show.