Antibody Testing Explained

Should you get a COVID-19 Antibody Test? Doctor Mark Wasserman says yes.

“I think it’s a good idea if for no other reason to help us make numbers and learn more about the virus,” Wasserman said. “This is all been new and anything that helps us learn about it is a good thing I think.”

Wasserman, who also serves as the Medical Director at AFC Urgent Care in Norwalk, said that an antibody test identifies the body’s immune response to a certain illness through testing a blood sample for antibodies. Antibodies are disease-specific proteins produced by the immune system to fight off a specific infection, and usually appear in the blood after one- to three weeks after infection, according to the CDC.

The COVID-19 antibody serology test specifically tests for the IgG antibody through a blood test. A positive result for IgG antibodies would indicate that the person may have been infected with SARS-CoV-2, the virus that causes COVID-19. The CDC says a positive result could also be potentially from a related virus, using the common cold as an example.

The antibody test is different from a diagnostic test, which requires a respiratory sample to identify if a person is currently infected with the virus. In other words, the antibody test only indicates past infection, as one could currently be infected with the virus and not yet have antibodies.

Wasserman estimates that AFC Urgent Care performs about 10 to 20 tests daily.

An antibody test is particularly helpful in identifying individuals who had contracted the virus but did not have any symptoms, otherwise known as asymptomatic infections.

What’s still unknown, however, is whether antibodies for COVID-19 would protect against future infection, or if and for how long the immunity could last. The flu is an example of a disease that can infect a person again even if they have overcome it previously. Researchers also don’t know what percentage of COVID-infected individuals are asymptomatic.

“Right now the test is more for people’s own information more than anything,” Wasserman said. “Only later down the road are we going to know if it’s going to help as far as being protective, but we at least partially we think it would.”

Since antibody tests are different from tests for active COVID-19 cases, there is more flexibility in who can get one. For AFC Urgent Care, the only requirements for testing are that the person has had no COVID-19 symptoms (listed on their website as cough, fever, body aches, or shortness of breath) for at least 14 days and must be over the age of 15.

If antibodies do provide immunity, it’s still unclear for how long this immunity would protect against future infection, so health officials emphasize that people who test positive on an antibody test should continue following social distancing guidelines and state regulations to protect themselves and those around them. That’s something the CDC underscores on its antibody webpage.

Nonetheless, Wasserman said there are “no negatives” to getting a test. Moreover, he said that results could be used to help identify trends such as what percentage of people in a certain test group have antibodies despite being asymptomatic.

In fact, Gov. Ned Lamont announced in a June 2 press release that Connecticut will launch a surveillance study with a randomized, representative sample of 1,400 residents who will be tested for COVID-19 antibodies. The study will examine three questions:  how many CT residents have been infected with SARS-CoV-2; how many of these infected residents have had little to no symptoms of the illness; and if there are any risk factors or characteristics related to getting the infection.

“Connecticut has an urgent need to understand the extent of prior infection with COVID-19 in order to guide our efforts to protect the state’s residents, mitigate the harms of the virus, and implement efficient programs in the areas of greatest need,” Gov. Lamont said in the release.

Additionally, an FDA release on COVID-19 antibody tests said that because people with antibodies can donate blood plasma to help people recover from COVID-19, taking the test could also increase knowledge of potential donors.

The release also reiterated that tests should have FDA emergency use authorization, meaning the FDA has reviewed the test for accuracy. The tests AFC Urgent Care uses are from Quest Diagnostic Labs, which are EUA certified, Ken Goldberg, the owner of AFC Urgent Care, said.

Goldberg said that antibody testing has been covered by insurance plans, though depending on the plan, a co-pay may be required. He added that the government is covering the cost for people without insurance and that people can call the center for more information on payment.

Stamford Health’s Wilton Draw Station is also offering antibody testing, but only with a doctor’s order. Wilton Primary and Special Care, will, on request, will virtually meet with patients to discuss the pros and cons of antibody testing, and can order one for patients; however, they are only doing that upon request from existing patients or people looking to become patients, not for the larger community. Danbury Hospital does not offer antibody tests; however, they are one of Nuvalence Health‘s three Convalescent Blood Plasma Donation Centers where eligible, recovered COVID-19 patients can register to donate blood plasma to people currently infected.

People who are interested in taking a test through AFC Urgent Care can schedule an online visit through the AFC Urgent Care website. Patients will then have a brief tele-visit with a doctor to discuss whether they think they have been exposed to the virus or have had any symptoms. Patients then can come to have their blood drawn at their convenience at the AFC Urgent Care location, and the results will usually come back within 1-2 days.

“It’s as easy as clicking a button,” Wasserman said.

The CDC also recommends talking to your health care provider about getting a test and about the results.