While we’d all love the pandemic to finish its long run, COVID-19  remains a reality. New variants emerge, cases climb, and healthcare systems quickly become overwhelmed. Every time a peak happens, the risk for exposure increases.

At-home rapid antigen COVID tests have been developed to help alleviate the pressure on our healthcare system and deal with this excess risk. Here’s everything you need to know about how rapid COVID tests are done if you need to take one yourself.

Disclaimer: This article isn’t intended as professional medical advice. If you have concerns about your COVID-19 status, please read through the CDC website for additional info.

What is a rapid antigen test?

You might be wondering, “How does a rapid COVID-19 test work?” Rapid testing for COVID-19 easily detects viral antigens. It works by collecting a sample by inserting a long swab into the nasal cavity or mouth. After that, the test detects any viral antigen proteins that show up in COVID-19 positive patients’ samples.

Most rapid COVID-19 tests can be done at home, while others need lab analysis. And although the at-home option is quicker, you can sometimes achieve mixed results.

Why does this happen? Rapid antigen tests take a snapshot of your viral load at the moment of the test itself.

Your viral load is how much of the virus is present in your body. If you test too early after exposure or before you develop symptoms, your viral load is lower, making it harder to detect.

If you have a negative COVID test result, it could be a false negative. You may have the virus but a low viral load — meaning you haven’t built up enough proteins for detection yet.

If you've received a false-negative result and still feel awful, you should confirm your results with an additional polymerase chain reaction (PCR) test. A PCR test looks for the virus’s genetic material, not just the proteins found on the virus, making it more accurate. Unfortunately, this type of test requires lab equipment, so it’s hard to do at home, and you’d have to visit a testing site.

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Who should be tested for COVID-19?

Specific symptoms can shift between variants, changing who should be tested and when. However, they all share commonalities:

• If you’ve been in close contact with someone who has a confirmed case, rapid COVID-19 testing is a must. Close contact is defined as anyone within 2 meters or less of you for 15 minutes or more. 

• If you feel sick with symptoms resembling SARS-CoV-2, you should be tested, even if you’ve received the COVID-19 vaccine. Symptoms can include fever, shortness of breath, coughing, body aches, and tiredness. 

• If you are a point-of-care staff member, like the staff at long-term care facilities, and your workplace cares for a vulnerable population where COVID-19 cases are more likely to emerge, you’ll need regular testing to protect these individuals. 

• If you’re heading to a large gathering where you could come into contact with many people, a pre-emptive test is recommended. This ensures that you’re not exposing others to COVID-19 infection.

When should I do an at-home COVID-19 self-test?

Keep in mind that when you are tested is critical: 

• If you’re exposed to COVID-19 through close contact but are asymptomatic, the recommended time to test is 5 days after your exposure notice. This is when your viral load is likely the highest. 

• If you’re feeling sick, it’s recommended that you test right away. 

• If you’re a healthcare provider working with vulnerable people, the recommended testing frequency is roughly two times per week. 

• For events, it’s best to test for COVID-19 on the same day or as close to the event as possible. You may be exposed to different pathogens in the meantime, rendering the test useless.

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How accurate are rapid COVID-19 tests?

You can receive a false positive or negative result if you don’t follow your test kit’s instructions, which is a risk if you conduct your test at home. False negatives can also occur if you have the virus but haven’t formed enough proteins for viral detection.

Other factors that increase or decrease the likelihood of which COVID-19 test is the most accurate:

• The type of COVID-19 test conducted

• How sensitive the diagnostics of that test are

• How thorough the sample collection process is

• Where the lab analysis is performed (at home or on-site)

The good news: Some over-the-counter antigen tests that have received emergency use authorization (EUA) are often accurate. Additionally, you can increase the likelihood of an accurate result by using at-home COVID tests that have been cleared by the FDA. 

How long does a rapid COVID-19 test take?

For the most accurate results, make sure you’re using an FDA-approved test and that you test 3–5 days after exposure or shortly after your symptoms of COVID-19 begin.

Testing tips:

• Make sure the test you’re using isn’t expired. If it’s outdated, accurate test results can’t be guaranteed.

• Make sure you have the correct setup for your test. This can include setting the room’s temperature or removing any contaminants in your testing space. Check the box of your specific test to learn more.

• Take additional precautions to ensure your oral or nasal swab sample isn’t spoiled. Clean the counter surface where you’re performing the test, sanitize your hands, and never touch the end of the swab used to collect the sample itself.

• Don’t deviate from the instructions on your test kit.

• Read the test results at the exact time your kit instructs you to. If you wait too long, the results may not appear accurate.

Additionally:

• Before a nasal swab, blow your nose to clear it of unnecessary genetic material. Ensure your face and the nasal area are free of skin creams or lotions that may interfere with the swab result.

• Don’t eat or drink for 10 minutes before an orally administered test to cut back on contamination.

• If you’re unvaccinated, more frequent testing is recommended. Fortunately, the cost of at-home COVID-19 tests is relatively low.

• Vaccinated individuals who contract COVID-19 are more likely to be asymptomatic, making rapid covid testing equally important to cut back on the spread.

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What do I do with my at-home COVID-19 tests results?

If the test shows a negative result:

• If you feel fine, you’re free to go on with your daily routine.

• If you test negative but remain symptomatic, isolate for at least a few days. There’s a chance you may have received a false-negative result. 

• Even if you tested negative, clean the surfaces in your living area and bedding to cut back on potential contamination. Take pain relievers (if necessary) to help manage any symptoms. 

• Once you’re done isolating, make sure to follow your local public health guidelines and regularly wash your hands. Avoid the gym and work out at home instead.

If the test shows a positive result:

• Immediately take steps to care for yourself in isolation if your symptoms don’t warrant hospitalization.

• Stay in self-isolation for 5 days, and wear a mask when moving around common areas in the home if you share your space with others.

• If your symptoms are difficult to manage, seek medical assistance.

• Depending on where you live, a positive test result could lead to contact tracing (informing those you’ve been in close contact with about your positive status). Contact tracing is usually conducted by a healthcare professional, but you’ll be asked to provide details to assist.

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