What you need to know about testing

Testing for active infection is one of the most important tools the medical community has to contain the spread of COVID-19. Knowing who to test, when to administer tests and which test to use are crucial to making sure testing is as accurate and effective as possible, says Washington University infectious diseases specialist Michael Lane, MD, Medical Director of Safety in BJC’s Center for Clinical Excellence.

Doctors and researchers have found that SARS-CoV-2, the coronavirus that causes COVID-19, is highly contagious and very dangerous — not only because it causes symptoms that can mimic other respiratory illnesses, but also because, in some patients, it causes few or no symptoms at all. These patients can unknowingly spread the virus to those at high risk of contracting severe or even fatal cases of the disease.

A prime goal of testing is to reduce the spread of COVID-19 by finding those people who are actively infected and making sure they don’t pass the virus to those around them.

At the beginning of the COVID-19 pandemic, there were no tests for SARS-CoV-2, simply because the virus was previously unknown in humans. As labs and manufacturers scrambled to develop and produce enough tests and testing supplies, there were worldwide shortages.

Now, as more labs and manufacturers develop and produce tests, they have become more available. BJC has been able to source tests and supplies through various vendors and manufacturers to test patients, employees and members of the public in its hospitals and in specially established drive-through testing centers.

”BJC has worked very hard to have enough tests available for those who need them,” says Dr. Lane.

But the number of tests and the supplies used in testing, such as nasal swabs and chemicals used to process tests can still be in short supply, so BJC is careful to use the tests only when indicated, says Dr. Lane.

There are many reasons that a patient may be tested. In BJC hospitals, patients with possible COVID-19 symptoms, patients who need emergency surgery or invasive procedures, and staff who are symptomatic or who have been exposed to an infected person are tested.

For the general public, testing is recommended for:

• people who have symptoms of COVID-19

• people who have had close contact (within 6 feet of an infected person for at least 15 minutes) with someone with confirmed COVID-19

• people who have been asked or referred to get testing by their health care provider or local or state health department

• those about to have surgery or invasive procedures

The BJC drive-through testing centers are available to those who have been referred by their care provider or who have completed the free online or phone pre-screening.

It’s not recommended that you go to the emergency room for testing unless you’re experiencing serious symptoms, such as shortness of breath or severe pain or if your symptoms progressively worsen.

BJC uses two basic types of tests to detect active COVID-19 infection — the polymerase chain reaction (PCR) test or the antigen test. The PCR test looks for the virus’s genetic material in the test sample while the antigen test looks for specific proteins found on the virus’s surface.

For both tests, a long cotton-tipped swab is inserted up the test subject’s nostril to collect material to test. The swab is sealed in a container and sent to the lab where it is analyzed.

PCR tests typically take longer to process but are more accurate at detecting the presence of the virus, says Dr. Lane. Most of the tests performed at the BJC drive-through testing centers and in the hospitals are PCR tests.

The antigen test can provide results more quickly than the PCR-based test. While not as accurate as the PCR test at detecting when the virus is present, the antigen test is very accurate at showing when someone is negative for the virus — which is valuable information to have when rushing a patient in for emergency surgery or an urgent procedure, for instance.

Many coronavirus antibody tests are also available commercially. These tests can indicate if a patient has developed antibodies to the virus, which may indicate that the patient has been infected in the past. Since it may take two or more weeks for a patient to develop antibodies to coronavirus, this test is not helpful for diagnosing an active coronavirus infection. Although BJC facilities offer antibody tests, there are very few situations where it is recommended.

Lab teams across BJC have stepped up and innovated to meet the sudden and urgent demand for COVID-19 testing by converting lab equipment and software and training personnel to collect specimens and process tests as accurately and efficiently as possible, says Dr. Lane.

The COVID-19 pandemic hasn’t canceled flu season, unfortunately. The labs have incorporated “multiplex” testing, which tests for the virus that causes COVID-19, as well as the common flu types at the same time.

For more information on COVID-19 testing, care and BJC policies, visit bjc.org/patients-visitors/covid-19-guidance.