Finally there is some positive news about the Covid pandemic: Pfizer's vaccine is being administered to healthcare workers this week, Moderna's vaccine could be distributed as soon as next week and now the Food and Drug Administration has approved the first at-home over-the-counter Covid-19 test for emergency use Wednesday.

While other at-home tests require you to collect your own sample to send to a lab for analysis, the new test created by Australian digital diagnostics company Ellume Health can be done completely at home and provide a result in just 15 minutes or less.

Here's what you need to know:

How does the home test work?

The Ellume Covid Home Test is an antigen test, which means it identifies specific proteins that are found on the surface of the virus when someone is infected with Covid-19.

How accurate is the test?

With all antigen tests, positive results are highly accurate and should be treated as a presumptive positive (meaning, you should act as though you have Covid until another test can verify it).

However, there is a higher chance of false negatives, because antigen levels can drop lower than what the tests can detect, according to the FDA. In other words, a negative antigen test result doesn't rule out a Covid-19 infection.

Clinical trials found that Ellume's home test correctly identified 96% of positive samples and 100% of negative samples in people with Covid symptoms. In people without symptoms, the test correctly identified 91% of positive samples and 96% of negative samples.

That means this test works best with people who have Covid symptoms, because antigen tests return positive test results when a person is most infectious.

So, while this test can save you a trip to a clinic and a long wait in line to get antigen tested, the results should be taken with a grain of salt. Getting a negative result from an antigen test doesn't give you the green light to behave as though you're uninfected. The most reliable way to tell if you have Covid or not is to get a PCR test, which is considered the gold standard.

"This test, like other antigen tests, is less sensitive and less specific than typical molecular tests run in a lab," Dr. Jeff Shuren, director of FDA's Center for Devices and Radiological Health said in a release. Compared to polymerase chain reaction (or PCR) tests, which look for genetic material of the coronavirus, antigen tests are less accurate.

Ultimately, however, this innovation will make it easier for people to get tested, "reducing the burden on laboratories and test supplies, and giving Americans more testing options from the comfort and safety of their own homes," Dr. Stephen Hahn, FDA Commissioner, said in a release.

How do you buy it and how much does it cost?

One bonus of the Ellume Covid Home Test is that it doesn't require a prescription to purchase, and it will cost about $30. (Everlywell's at-home PCR test costs $109, involves shipping a sample to a lab, waiting a day or two for results and requires a prescription in some states. Pixel's test is $119 out of pocket and can be purchased OTC, but also has to be sent to a lab.) Under the CARES act, private health insurance policies must cover the cost of Covid testing.

You'll be able to buy the test from online retailers and in pharmacies in January. Ellume expects to produce 100,000 tests a day by next month, and 1 million tests a day by June. (To put this in perspective, the reported seven-day average number of tests done in the U.S. is 1.9 million.)

How do you take the test?

The test kit comes with four different parts: a sterile nasal swab, a dropper, processing fluid and a small Bluetooth-connected device that analyzes your sample and syncs with a corresponding smartphone app. A video on the app shows you how to properly take the test, because it is somewhat complex.

To use the test, you first have to turn on the analyzer and pair it with your smartphone. Then, you empty a vial of special processing fluid, into a dropper device.

Next, you insert a swab in your nostril and rub the tip of the swab around your nostril three times, and repeat on the other nostril. Unlike a PCR test, which requires a nasopharyngeal swab to reach far back behind the nose, the Ellume test only enters the nostril.

From there, the swab gets screwed onto the dropper, and your nasal sample mixes with the processing fluid. Finally, you have to squeeze five droplets of fluid into a port on the analyzer device, and wait for the test results to show up on the app.

The test works on people ages 2 and up (though only people ages 13 and up can administer the test themselves), according to the FDA.

Check out: When Dr. Fauci and other experts say you can expect to get vaccinated for Covid-19

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