Getting tested for COVID-19 can be confusing. It is still a fairly new process for most people, and having questions or concerns is very understandable. To help clear up the confusion, we asked Dr. Amanda Novack, Baptist Health Medical Director of Infection Prevention, the top questions you may have about COVID-19 testing.
When should someone get tested?
There are actually a lot of scenarios where someone might need to get tested for COVID-19.
The most common right now would be someone who develops symptoms:
- Shortness of breath
- Lost sense of smell or taste – that’s pretty specific to COVID-19 and people should be tested right away in those situations
Another time that’s common for someone to be tested is if they know that they’ve been exposed to the virus. In that case, it takes about five days for someone to turn positive themselves after they’ve been exposed. So you don’t necessarily want to get tested the day you find out that your friend tested positive – you want to make sure there have been several days since that exposure and then get tested.
Another time that people are tested is before travel or before spending time with a loved one who is extra vulnerable. As we go into the holidays, that’s a very reasonable thing to do to ensure that everyone who is visiting together is negative before they visit.
Should I take a rapid test or PCR test?
For people that don’t have symptoms, a PCR really is a better test. It’s much more sensitive – it can pick up on even tiny, tiny bits of the virus. An antigen test is faster, and it’s pretty good if someone has symptoms. It is positive when they have COVID, and they’re sick with COVID. But an antigen test is not really sensitive enough to pick up on those asymptomatic cases, or those people who are infected but don’t have any symptoms of it yet.
What is the difference between the two most common tests?
So there are lots of different machines that can run a COVID test, but we basically break them down into two categories – an antigen test and a PCR test.
An antigen test is testing for a protein on the COVID virus. That test is very fast – they tend to be 15 minutes; they’re relatively cheap and easy to perform in a clinic or outpatient setting. But they are not as sensitive as the PCR, which is testing for genetic material. An antigen test is great if you need quick results to find out if these symptoms that you have are actually related to COVID.
The PCR test can pick up the virus even in tiny, tiny amounts before someone develops symptoms or long after their true infection has passed. So the PCR is a good test if you don’t have any symptoms but you really want to prove for sure that you don’t have the virus. PCR tests can take anywhere from an hour to several days to get results. Most PCR tests are send-outs to reference labs, and those can take a day or two to come back. But there are a lot of places in Arkansas now that can do the PCR on-site, and those machines run anywhere from one and a half to four hours. So, our turnaround time is better than it was, but when you really need to know in the next little bit if your symptoms are related to COVID, an antigen test is often the faster, easier test to get.
What about the mouth swab or home test?
There are several different ways we can collect a COVID-19 test.
The virus replicates the most at the back of our nose, and so that’s the most sensitive test. If you can get a sample from the back of the nose, it’s most likely to pick up on any virus if it’s there.
But we do have some other tests, some other machines that are validated for the front of the nose or the back of the throat. So for people that have had sinus surgery or small children, those tests can be a good alternative. They’re not quite as sensitive as the back of the nose, but they can still be a pretty good substitute.
The home tests have not quite gotten to where we trust them yet. There might be a time that those are valid, and it’s not that they’re completely wrong, but they’re really not sensitive enough to pick up on every case, and they’re not always as specific. That means sometimes it can say it’s positive, when it’s not really COVID-19. So we don’t really trust those to make clinical decisions.
What is the difference between isolation and quarantine?
One bit of confusion is the difference between isolation and quarantine, because, in a semantic sense, they really mean the same thing.
But, when public health experts or infectious disease doctors are talking about quarantine and isolation, isolation is what we do when someone is known to be positive. They isolate from the rest of the community.
Quarantine is when someone has been exposed, and so they need to stay home as well and not come in contact with anyone else because they could turn positive at any moment. A quarantine period has to allow for the variations in the incubation period. That’s what we call the period between when someone’s exposed to the virus and when they actually test positive themselves. And that time can be anywhere from three to 14 days, so that’s why for so long we had people quarantining for 14 days.
Through more science, the Centers for Disease Control and Prevention (CDC) has found that most of the time, if someone hasn’t developed symptoms by day 10 after exposure, they’re probably not going to. So, the CDC recently changed the quarantine period for exposed people to 10 days. They further went on to say if, at seven days after your exposure you have a negative PCR test, we’re confident enough that you’re not going to develop COVID-19 that it’s reasonable to end your quarantine at that point – keeping in mind that some people do develop COVID a little bit later than that and we should always still watch for symptoms.
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