A doctor explains why some people faint when they get a coronavirus test

• While most people find the coronavirus test uncomfortable, in rare cases, it may make people faint.
• An ear, nose, and throat specialist told Business Insider the reaction is related to a "primitive" response intended to protect you from running out of energy and oxygen when diving into icy water.
• Because many clinicians performing the tests aren't experts in nasal anatomy, their technique may make a difference in how uncomfortable it is for a patient, too.
• Visit Business Insider's homepage for more stories.

Jane Pauw weathered such a severe case of COVID-19 she once had to crawl to get herself water. She passed the feverish days in a fog too heavy to allow the clarity to even be concerned, and had to rest if she ventured downstairs.

And yet, the 60-year-old pastor in Seattle told Business Insider the worst part was before all of that, when she got a coronavirus test in early March.

The test — technically known as a RT-PCR test, which detects whether the virus is currently in your body — involves a healthcare provider pushing a thin, plastic nasal swab three to four inches along the floor of the nose through the nostril.

The goal of the coronavirus test is to extract sputum — the material that gets ejected through coughing, sneezing, spitting, and singing — in order to test it for some of the coronavirus's genes, Business Insider's Hilary Brueck and Samantha Lee previously reported and illustrated.

While momentarily uncomfortable for most, it was "excruciating" for Pauw, who already had swollen nasal passages and had to drive 45 minutes to Tacoma, Washington, to get one.

"It feels like being stabbed, to me, in a really sensitive place and then having it be twisted," she said. "And then, they had to do it twice."

Even when it was over, Pauw didn't feel better. In fact, she and her husband had just gotten on the freeway home when Pauw passed out. Fortunately, she wasn't driving. "That was a horrible experience," she said. "That was the very worst day of it all."

Pauw's doctor told her she'd had a "vasovagal reaction." Here's what that means and why, though it seems to be rare, the coronavirus test can cause it to happen in some people.

Testing reactions vary from no big deal to excruciating

Reports of how bad the COVID-19 test really is vary widely, even sparking minor controversies.

"It's kind of like breathing in water through your nose," Wesley Schrock, a campaign manager in Washington, D.C., told the New York Times.

One member of a private Facebook group for COVID-19 survivors told Business Insider: "It felt like I was cleaned from behind my eyeball," leading to an hour-long headache. Several others said they cried. Many used the word "intense" to describe it.

One survivor in the group, though, said "it wasn't that bad." And, when President Trump told reporters in mid-March that there is "nothing pleasant" about it, model Chrissy Teigen quickly shot back, tweeting that there are a lot more painful things in life, namely childbirth.

But for most, the procedure causes "a five- to eight-second shock of unpleasantness," Dr. Shawn Nasseri, an ear, nose, and throat surgeon in Los Angeles, told Business Insider. It can also come with some throat pain due to the swab reaching the throat or tonsils.

For the "small proportion of people" who have a strong reaction to anything in their nose, Nasseri said, it can also lead to sneezing, which is the body's way of trying to expel anything unwanted, like dust or bacteria, from the nose.

Fainting seems to be rare, but understandable

Reports of people fainting are rare, and are likely to be "connected to more primitive reflexes," Nasseri said.

Specifically, the "seal dive" or "diving" reflex, which all mammals experience when submerging their faces submerge in icy​ water.

The reflex shunts blood away from the skin and toward the inner organs, and causes a decrease in heart and breathing rate in order to conserve energy and oxygen for the heart and brain.

The swab may initiate a similar reaction and cause some people to faint from the lack of blood flow to their brain, just like some people faint at the sight of blood. (In at least one case study, though, fainting or feeling lightheaded can actually be a symptom of the virus, not a reaction to the test.)

The actual fainting episode is medically known as "vasovagal syncope," and may be preceded by pale skin, lightheadedness, tunnel vision, nausea, clammy sweat, or other symptoms, according to the Mayo Clinic.

The experience is usually harmless and doesn't require treatment, and people tend to recover within a minute. Still, it can be dangerous if you injure yourself or someone else (like if it happens behind the wheel) while passing out.

If you have a history of fainting after, say, a blood draw or vaccine, make sure you're securely seated or lying down when given the test and wait at least 15 minutes afterward to get up.

A clinician's expertise, as well as patients' 'grimacing,' can make a difference too

In 20 years of practice, Nasseri said, "no one has ever asked me to repeat a nasal swab 3 inches into the naso-pharynx, but only one person has passed out on me."

Results could understandably be different among potential COVID-19 patients, who are, necessarily, receiving tests from clinicians without a nose surgeon's knowledge of the body part's anatomy.

"There is definitely a learning curve with the technique in terms of how much resistance one pushes against in the nose and therefore 'hurts' the patient," Nasseri said. "It is similar to playing the 'Operation' game, but blindly as most clinical personnel swabbing the nose are doing it without seeing inside the nose."

On the other hand, inexperienced clinicians may not insert the swab far enough, in which case it may be more comfortable but less effective.

Patients' (often reflexive) reactions to the uncomfortable procedure can affect how much it bothers them too, Nasseri said. "When we grimace or make a face, it actually tightens the nostrils and tends to force swabs up into the nose instead of along the floor of the nose," he said. "This definitely makes it more unpleasant for the patient."

Ultimately, though, he said the plastic swabs are "smaller, softer, and thinner than their cotton counterparts and are usually very well tolerated." The benefits outweigh the temporary discomfort. "Please be patient, and get through it quickly."