What You Need to Know about COVID-19 Testing

Author

Photo of Will Tollefson, MD Emergency Medicine

William Tollefsen, MD, Vice Chair of Emergency Medicine and Urgent Care

As the holiday season begins amidst a rise on coronavirus cases, it feels like everyone is looking for a COVID-19 test.

Recently, as part of our One Healthy Boston partnership with WCVB-TV, I answered questions about COVID-19 testing on Facebook Live. 

If you missed the broadcast, you can watch it on YouTube

Here are answers to some viewer questions about COVID-19 testing.

How do COVID-19 tests work?

There are two different categories of coronavirus tests: Diagnostic tests and antibody tests.

A diagnostic test determines if you currently have COVID-19 virus in your body. 

Antibody tests look for antibodies, which your body makes in response a COVID-19 infection. It can take several days or weeks for antibodies to show up in a test, so these are given to patients who suspect they were infected, but were never tested for the active virus.

And, as a reminder, antibodies do not mean you are immune to the virus. 

What kinds of diagnostic COVID-19 tests are there?

One is a molecular test, which looks for actual DNA fragments from the virus itself. This is also called a PCR test.

The other is called antigen testing, which tests for a protein that’s found on the surface of the virus. 

Which COVID-19 diagnostic test is most accurate? 

Results from a molecular test, either positive or negative, are highly accurate.

A positive result on an antigen test is very accurate. However, antigen tests are less sensitive, which can lead to some false negatives. 

This is why some places don’t accept negative antigen test results for returning to work or school, and why some providers may order a follow-up molecular test after a negative antigen test.

Are rapid COVID-19 molecular tests accurate?

Tests like the Abbott ID NOW test, which we use at Health Express, South Shore Health’s urgent care offices, are very accurate. 

Rapid PCR tests detects the presence of COVID-19 DNA from a sample taken via a nasal swab. (This isn’t a deep brain probing—it’s just along the tip of your nose.)

A machine about the size of a toaster oven runs the test, and provides a result in as little as 15 minutes.

How can I get a rapid COVID-19 test?

South Shore Health offers rapid COVID-19 PCR testing at Health Express. To get an appointment, you need to visit the Health Express website and click the button at the top of the page to complete a quick questionnaire. After that, you’ll also have a brief telehealth visit with a member of our team prior to your test.

Why are COVID-19 tests still hard to get?

The nation’s supply chain is having a hard time keeping up with demand for the swabs, solutions, and other critical components needed to conduct a COVID-19 test. Our team will always let you know if we can’t do the rapid test due to any shortages.

We know it’s frustrating to wait, especially if you need the test for travel. But for symptomatic patients, you’ll still have to quarantine at home, even if your test is negative, to stop the spread.

If we don’t have supplies for a rapid test, Health Express offers the Quest Diagnostics COVID-19 PCR test. Turnaround time for these tests vary and are shared via Quest’s patient portal once they are available. If your test is positive, Health Express will also call you.

Can you test positive after quarantining for COVID-19?

You absolutely can. COVID-19 test results depends on the level of virus in your body. If you had symptoms—such as a fever, cough, and tightness in the chest—and quarantined for 14 days and then took a molecular test, it may detect the low levels of virus still in your body.

If you test positive after quarantine, it’s best to stay in quarantine until you get a negative test.

As Massachusetts continues to see a climb in cases, we anticipate the demand for testing will continue to grow.

Bookmark South Shore Health’s website about COVID-19 to get the latest updates on testing, safety measures, and more.
 

Learn more about Health Express urgent care.

Author

Photo of Will Tollefson, MD Emergency Medicine

William Tollefsen, MD, Vice Chair of Emergency Medicine and Urgent Care