FDA Authorizes First Point-of-Care Antibody Test for COVID-19

The Food and Drug Administration (FDA) has granted an emergency use authorization (EUA) for the first point-of-care antibody test for COVID-19.

The Assure COVID-19 IgG/IgM Rapid Test Device, a simple fingerstick blood test, was previously used for laboratory testing to detect antibodies to SARS-CoV-2 (the virus that causes COVID-19) in patients.

The FDA explained in a press release that the EUA was re-issued to allow the test to be used in provider's offices, hospitals, urgent care centers, and emergency rooms rather than having to be sent to a central lab for testing.

“Authorizing point-of-care serology tests will enable more timely and convenient results for individuals who want to understand if they have previously been infected with the virus that causes COVID-19,” FDA Commissioner Stephen M. Hahn, MD, said in a statement.

Hahn also noted that the new point-of-care test will free up laboratory resources for other types of testing. “Until today, serology test samples were generally only able to be evaluated in a central lab, which can be time-consuming and use additional resources to transport samples and run the test," he said. "As more and more point-of-care serology tests are authorized, they will help conserve those resources and may help reduce processing time for other types of COVID-19 tests, as less time is spent on serology tests.”

How Antibody Tests Work

As defined by the National Institutes of Health (NIH), antibodies are molecules that are produced by the immune system to fight infection.

After a person has been infected with SARS-CoV-2, they will typically develop antibodies within seven to 10 days, Joseph F. Petrosino, PhD, chairman of the Department of Molecular Virology and Microbiology at the Baylor College of Medicine, tells Verywell.

“With many viruses [antibodies] can be detected years after an infection,” says Petrosino. “Interestingly—and what has raised some alarm—is that with SARS-CoV-2, the antibodies seem to disappear in many individuals after three to six months following an infection.” Petrosino adds that this is “not unheard of"—especially with respiratory viruses.

A COVID-19 antibody test looks for the presence of SARS-CoV-2 antibodies, Jamie Alan, PhD, an assistant professor of pharmacology and toxicology at Michigan State University, tells Verywell. “An antibody test means that the individual had COVID-19 in the past," she says. "How long ago is hard to tell, as we don’t know how long antibody-mediated immunity lasts.”

According to the FDA’s EUA, the newly-approved test only requires a single drop of blood, which is applied to a test strip. After 15 minutes, colored lines on the strip will reveal whether a patient has IgMs (the antibodies that are produced soon after infection with SARS-CoV-2) and IgGs (a form of antibodies that are produced later after an infection).

Limitations of Antibody Tests

Richard Watkins, MD, an infectious disease physician in Akron, Ohio, and a professor of internal medicine at the Northeast Ohio Medical University, tells Verywell that “there are a whole host of issues surrounding" antibody testing.

How Long People Have Antibodies Is Still Unknown

In its press release, the FDA made clear that it’s still unknown how long people might have antibodies to COVID-19. The agency also stressed that it’s still unclear whether the presence of antibodies will protect a person from future infections.

The FDA states that people "should not interpret results from a serology test as telling them they are immune, or have any level of immunity, from the virus."

It is still important to protect yourself and others with mask-wearing, social distancing, and hand washing.

Test Does Not Detect Virus

The FDA also noted in its press release that antibody tests “only detect antibodies the immune system develops in response to the virus—not the virus itself.” The test cannot tell if someone currently has COVID-19.

The test also might not provide a certain answer as to whether a patient has had a previous COVID-19 infection. “If the test is negative, [the patient] likely has not been exposed to COVID recently,” Alan says. “However, it’s possible that they were exposed but did not have a complete immune response.”

False Positives

There is a risk that someone may have a false positive if they recently had another coronavirus, such as the common cold, Watkins says.

The FDA also warned of the risk of false positives noting that, “in a population with low prevalence, even high-performing antibody tests may produce as many or more false results as true results because the likelihood of finding someone who has been infected is very small.”

Benefits of a Point-of-Care Antibody Test

In general, “antibody tests are useful to help determine what the community-wide infection rate is,” Petrosino says. However, he adds that a test that can be run at an urgent care center, hospital, or doctor’s office is not necessarily needed to do that.

Point-of-care antibody tests are not always as reliable as laboratory-based tests. “You often sacrifice on accuracy and sensitivity when using point-of-care tests compared to laboratory-based antibody assays, which often can determine not only whether or not you have antibodies, but how much antibody you produced as a response to infection,” Petrosino says.

Alan explains that a point-of-care antibody test could potentially save laboratory resources, but it's unclear how much of an impact that would actually have.

Having a finger stick test could make people more open to antibody testing compared to having a full blood draw test. “It is more difficult to run quantitative laboratory tests without a blood draw,” Petrosino says. “For surveillance studies to be meaningful, a significant number of participants is needed. So, anything helping to boost participation by volunteers is helpful.”

Experts say a point-of-care antibody test isn’t necessarily needed—or at least, not needed as urgently as other tests. “The need for the test to be run point-of-care isn’t as great as for [diagnostic] tests for the virus itself,” Petrosino says.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.