Carla M. Delgado is a health and culture writer based in the Philippines.

Heather Mercer is native to Northwest Ohio (go Walleye!) and graduated from Loma Linda University with two doctorate degrees (psychology and public health). She is currently a professor at Owens Community College, as well as a fact-checker for Verywell Health. She has gained experience in a variety of settings, ranging from corporate wellness and preventive medicine, to mental health, chronic disease, and end-of-life care. 

People are increasingly opting for at-home rapid COVID tests because of their convenience and quick turnaround time. You can now even order free testing kits from the government.

It's crucial you swab your nose correctly to minimize the chance for error, and a possible false-negative test. But the instructions for these at-home tests can be complex and tricky to navigate.

Here’s what you should keep in mind when swabbing your nose for at-home COVID-19 tests.

Before starting, make sure that the test is authorized by the Food and Drug Administration (FDA) and has not yet expired, and then read the user manual.

“Proper technique is essential to ensuring a more accurate result, so it’s important to follow the instructions given to you with the test,” Christopher Scuderi, DO, a family physician at University of Florida Health in Jacksonville, told Verywell. “Some of the more popular tests may have a demonstration video online to help.”

Antigen tests normally require that the swab be inserted into the nostril. In general, this is how the specimen should be collected:

“The instructions for the different manufacturers are a little different from one to another,” Gigi Gronvall, PhD, senior scholar at the Johns Hopkins Center for Health Security at the Bloomberg School of Public Health, told Verywell. Carefully follow the instructions of your own test exactly as indicated.

To get accurate results, you have to obtain a good sample. The test is intended to pick up certain proteins from the virus, so the goal is to swab the cells that live on your nasal walls.

“You are looking for active virus,” Gronvall said. “Viruses need to get into your cells to make copies of themselves. They enter, make a ton of copies of themselves, burst open the cell, and then infect more cells. When you swab your nose, you are looking to see if there is virus replicating there.”

If a rapid antigen test requires only a nasal swab, it’s best to refrain from collecting a specimen from anywhere else other than the nose, like your throat.

"The test is only as accurate as the quality of the sample you get, so closely follow the directions for a nasal swab as indicated by the manufacturer," Scuderi said.

It’s OK if you have a cold and get mucus on the collection tip of the swab, but your target should still be the cells of the nasal walls. The test doesn’t care if you get “snot” on the cotton swab, but you need to know if the virus is actively replicating in the cells of your nose, Gronvall said. For good measure, blow your nose beforehand so you don’t collect old proteins that live in the mucus.

“Blood has been associated with unreliable results in some studies, so best to avoid this if possible,” Scuderi said.

When swabbing the nose for a rapid at-home antigen test, make sure that you rub the collection tip of the swab against the walls of your nose. Blow your nose beforehand so that you get a good sample.

A nasal swab can be uncomfortable, but it must be done correctly, otherwise, the test will not provide you with accurate results.

“The risks of not performing the test correctly is almost always going to result in a false negative,” Gronvall said. “You could be infectious and could be putting others at risk.”

If you have doubts about the accuracy of the result, you could try repeating the test over the next few days since your viral load could increase over the course of a few days.

“A good rule of thumb is that if you are symptomatic and have had a negative rapid at-home test consider repeating it or scheduling a molecular PCR test to verify it is truly negative,” Scuderi said. “This is especially important if you have been exposed to someone who has tested positive for COVID-19 and you are currently symptomatic.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life.

Thank you, {{form.email}}, for signing up.

There was an error. Please try again.

Centers for Disease Control and Prevention. Self-testing.

Thank you, {{form.email}}, for signing up.

There was an error. Please try again.