As the COVID pandemic continues to rage on, we look for glimmers of hope everywhere—and Amazon might be the newest bright spot: You can now buy an FDA-authorized COVID-19 test on Amazon . But before we go rushing off to 'add to cart,' there is a hugely important caveat: They may not be as accurate and we'd like them to be.

Here's what you need to know about the at-home COVID tests sold on Amazon.

The tests are made by manufacturer DxTerity and are authorized by the FDA under an Emergency Use Authorization (EUA). They can be used for symptomatic or asymptomatic testing (whether or not a person has COVID symptoms). They cost $110 each, or you can buy a pack for 10 for $1,000. When the test arrives, you register at the company's website. Wait 30 minutes after eating, drinking, smoking or chewing gum, then fill a little vile with saliva and ship it using a pre-paid label via Fed-Ex. Results should be available electronically within 24 to 72 hours.

At-home COVID testing is an important step because it offers a (very convenient) way for people to advocate for their health and well-being. If someone does not have easy access to a testing location, at-home tests are a great option—getting a positive COVID test means that people can be more proactive about monitoring their symptoms, seeking medical attention and quarantining to avoid transmitting COVID to others.

This is exciting news—but with a huge caveat: Right now, a negative COVID test does not mean much, and should not be used as 'permission' to soften your adherence to COVID safety measures (such as wearing a mask, social distancing and not gathering with people outside of your home).

The manufacturer guidelines state , "Results of the test should not be used as the sole basis for patient management decisions." This means that if you get a positive at-home test, your physician may still suggest doing a nasal swab to confirm the result. And, it means that a negative test does not necessarily mean that you definitely do not have COVID. This last piece is hugely important, and I am going to repeat it obnoxiously:

A negative COVID test does not mean that you do definitely not have COVID.

Here's why:

They are not as accurate as we'd like. When we look at testing of any kind, we consider the sensitivity and specificity. The sensitivity refers to a test's ability to accurately report that someone has a disease or illness, while the specificity of a test refers to its ability to accurately classify someone as being disease-free.

These terms exist because tests are not perfect—COVID tests are no exception. Sherry Dunbar , Ph.D., MBA, Luminex's senior director of global scientific affairs, told Healthline that at-home tests are "likely to have lower sensitivity and specificity than lab-run tests."

Two more important terms to understand are false-positive (when a test says someone has a disease but really they do not) and false-negative (when a test says someone does not have a disease but really they do).

It's this last one, the false-negative, that can cause big trouble; depending on the type of test and the timing the test is done, COVID tests have a 20 to 100% chance of reporting a false negative . That means that at least one of five people who get a negative test may actually have COVID.

This can happen because someone tested too early (before the virus ramped up enough to be detectable), because testing was not done properly or simply because the tests are not perfect.

In other words, and once again, a negative COVID test does not mean you can safely gather indoors or without masks. I am going to be blunt: Continuing to use negative COVID tests as permission to let down our guard means that we are going to keep getting and giving COVID.

Now, there is hope. Other manufacturers are also hard at work making at-home COVID tests and these may have much higher accuracy. Abbott is making millions of its BinaxNOW tests (which will be significantly less expensive at $25 each) and they should be available soon. And Detect is working on an at-home test that should be $50 each. Both of these companies say that results will be available much faster without needing to mail in the test.

In the meantime, if you'd like to test yourself for COVID by all means go for it. You can find them on Amazon below here .

If you get a positive result, call your health care provider immediately for their guidance on the appropriate next steps. Per the test manufacturers, if you have emergency symptoms such as "trouble breathing, persistent pain of pressure in the chest, new confusion, inability to wake up or stay awake or bluish lips or face," seek immediate medical attention (even if the test is negative).

But please remember that these tests are not foolproof. Dr. Dunbar wrote that "On the whole, they are a better option than not having these tests available at all, but because of the potential for lower overall accuracy, they still should be confirmed and require physician follow-up for appropriate medical direction."

Continue to be vigilant and safe, and we will get through this .

Here's where to buy the at-home COVID test on Amazon:

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