Coronavirus Updates & Hospital Visitor Policy

So, What is Immunity Testing?

Celia Spell
April 29, 2020
Medical diagnostic test referral form with a pen hovering over the Serology checkbox.

Scientists across the world have been scrambling to learn more about COVID-19 since it first made its appearance in 2019. Many researchers are working on vaccines, while others are working on treatment options, and in the meantime, there are those hoping to understand how we develop immunity to COVID through what is known as serology testing.

Serology testing looks for antibodies and immunoglobulins in someone’s blood, which are proteins that appear as a part of your immune system’s defense against an illness or disease. The serology test that is being used for COVID is hunting for an antibody known as IgG, which would indicate long lasting protection against an infectious disease like this one.

“In most other infectious diseases there is an immunoglobulin called IgM that typically rises very quickly after you’ve been exposed to something infectious but doesn’t tend to last very long,” said MUSC Health Chief Quality Officer Danielle Scheurer, M.D., MSCR.“ IgG on the other hand, takes a little bit longer rise, typically between 10 and 14 days, but it tends to stick around longer.”

She says one thing that makes testing for antibodies to COVID a little more difficult is that we don’t know how long an antibody like IgG will stick around and provide protection from reinfection. COVID hasn’t been around long enough to determine those averages. But the first step to learning more is to start conducting serology testing, which involves a two-part strategy.

“Firstly, MUSC has a team of researchers that has been poring over all the studies from the FDA and the European counterpart trying to find a test that would work well,” said Scheurer. They’re looking for one that is robust, can handle high volumes but is reliable, which led them to order tests from a company called Abbott to begin testing on healthcare system care team members and community first responders this week.

Secondly, MUSC is developing its own in-house serology test in collaboration with Clemson University and University of South Carolina. According to Scheurer, the test has already been built, and it is being validated to reduce the risk of falsely positive and falsely negative results.

Scheurer says it is important for MUSC to develop its own in-house testing capabilities to ensure an ample supply of tests and to reduce the risk of shortages. “Hospitals and healthcare systems have had to learn the hard way throughout all of this that any one product line can be shut off in a matter of hours. That’s why we decided to take a two-pronged approach.”

The test only requires a blood draw and would have a turnaround time in the lab of just a few hours. Starting on a voluntary basis with MUSC Health employees, patients will log on to MUSC Health Virtual Care to determine if they are a good candidate for serologic testing. For instance, if you’ve had any COVID-like symptoms in the last two weeks, you would need to wait longer to take the test in order to give your body more time to develop long-term antibodies. Those who do qualify will be directed to one of MUSC Health’s clinical sites to receive the test.

Once we have completed the first phase of testing, MUSC will increase and expand opportunities to the Charleston community. Patients will be able to schedule a virtual appointment with a care team member to understand what their results mean for them and to answer any questions they may have.

Conducting serology testing is just another step hospitals and healthcare systems like MUSC Health are taking to bring some peace of mind to patients. But the results of the test should not be used to determine whether someone should or shouldn’t go back to work or continue with social distancing measures. “You can 100% certainly still bring COVID home with you, even if you exhibit the right antibodies against it,” Scheurer said. “It can be carried on your hands or on your clothes, so it’s still important to be careful until there is a vaccine available.”

Serology testing brings us one step closer to understanding COVID-19’s presence in the community as well as our immune response to it.

“All of these things that we’re currently enduring are life changing and very difficult to sustain. And if people are going continue to make medium- or long-term sacrifices, it's got to be because they truly understand what we're up against as it relates to COVID.”