How long you should wait before getting a coronavirus test if you think you've been exposed
- If you are exposed to someone with the coronavirus, it usually takes at least a few days for the infection to incubate in your body.
- That's why public health experts recommend waiting 5 to 7 days after any exposure to the virus to get tested.
- Stay in quarantine for 14 days from your exposure, no matter what your test results may show, and make sure to get one final test before you re-emerge into the world.
- Visit Business Insider's homepage for more stories.
If you've recently been around someone who has Covid-19, the disease caused by the novel coronavirus, getting tested should not be the first thing on your to-do list.
"If you've been exposed, get into quarantine," Virginia Tech professor and public health expert Lisa Lee, who spent 14 years previously working at the Centers for Disease Control and Prevention, told Insider.
"Immediately separate yourself from everyone else. And do that for 14 days."
On average, it takes about four to five days after someone is infected with the coronavirus for them to show symptoms of illness, but the virus's incubation period can last anywhere from two to 14 days, which is why the recommended quarantine period is two full weeks, no matter how you may feel during that time, or what your test results may show.
"This idea that we've been exposed, and we're just going to wait around [for a test] to see if we're positive is a bad idea," Lee said.
There is no approved vaccine against the virus yet, and no good course of treatment that works reliably for everyone.
So even if you never show any signs of illness during quarantine, you could still put others at risk of infection, or even death, if you're not careful.
The coronavirus can also spread easily from asymptomatic people who aren't showing any signs of illness. According to the CDCs current best estimates, asymptomatic spreaders may account for 40% of all coronavirus cases. So it's critical for people to stay home when they've been exposed to a sick person during this pandemic, even if they feel alright.
Get tested about 5 to 7 days after your exposure
Once you're in quarantine, the best time to get an accurate test is, generally speaking, about a week after you've been exposed to the virus.
The Minnesota Department of Health recommends testing "five to seven days after" an exposure event.
If that first test comes back negative, it's worth getting tested again, around 12 days after the initial event, in case the virus took a while to present.
For those who do end up feeling sick, there is still a good window of opportunity for the virus to spread, a sneaky period before symptoms arise, when people transmit this virus very well. This issue of pre-symptomatic spreading is one reason why the coronavirus pandemic has been such a tough one to combat.
"You become infectious some time between when you're infected and when you test positive, we don't know exactly when," Lee added.
Often, the day before symptoms arise is when people pass their infections on to others best.
So avoid any social mingling, wear a mask if you have to be around others in your household, and be quiet if you absolutely must share space with other people (briefly) during your quarantine. At home, continue to keep a good amount of space between yourself and others.
If your test is positive, try to isolate yourself in a separate room, and use a separate bathroom from everyone else, as the CDC suggests. If you can't stay in a separate room, make sure there's good airflow: open a window if you can, so that the virus won't remain airborne very long.
The best test to get is a lab test
The gold-standard coronavirus test is a nose and throat swab test that has to be taken to a lab to yield results. This is called an RT-PCR test and it is hunting for the presence of some of the coronavirus' tell-tale genes.
This test, as long as it is administered properly, is "likely" to find the virus in your body, Lee said, "if it's there."
To administer this test, a clinician typically swabs deep inside a person's nose and throat to extract sputum — the gunk that gets ejected through coughing, sneezing, spitting, and even talking. Results are usually returned within a matter of days.
Rapid tests are good for quick screening, but less precise than lab tests
There are newer, faster coronavirus tests, too. These are called rapid tests, as they often yield results in as little as 15 minutes, with no lab work. But there is a cost to that speed: they're less precise at picking up infections.
"Instead of looking for the genetic material of the virus, it looks for a little piece on the coating of the virus," Lee said. "So it's just looking for a particular protein that sits on the outside of the virus."
Generally, these rapid tests are best used as screening tools (for major outbreaks, or screening vulnerable groups, like frontline workers). Positive results are best confirmed with a lab test.
"Point-of-care tests are extremely useful if you have symptomatic people, or if you're contact tracing, or if you're in a place like a nursing home where we're going to be testing repeatedly," Admiral Brett Giroir, director of diagnostic coronavirus testing in the US, recently told reporters on a call about these rapid tests.
A negative rapid test result does not necessarily mean you can end your quarantine
Rapid tests are not, then, a free pass to go party, or to end a quarantine early.
"A negative test one day does not mean you're going to be negative the next" Giroir said.
As with any COVID-fighting tool, tests are but one part of an integral system, and must work together with other virus precautions and measures.
"Any lab test should always be used in conjunction with other factors," Philip Ginsburg, a senior medical director for Abbott's rapid diagnostics wing, previously told Business Insider. "The patient's clinical presentation, the history, other test results. It's very seldom that a physician would make a call, you know, purely just on a single standalone test, without getting all the other circumstances."
Get tested again at the end of your quarantine
As you wrap up your quarantine, it's a good idea to go get one last test, just to help assure it's safe to venture back out into society.
"If you want to get a test while you're in quarantine for 14 days, fine, but you definitely need a test at the end of it to make sure that you can come out," Lee said.
If that test comes back positive for the virus, talk with your health care provider about how long you should continue to wait, before emerging again, to make sure you're no longer contagious.
"That varies for people depending on whether they have symptoms, when they have symptoms, how long they have symptoms, that kind of thing," Lee said. "So it's something that is really important to do with a health care provider."
Blake Dodge contributed reporting.
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