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Antibody testing arrives in Tampa Bay, but doctors are wary of accuracy

It’s unclear if patients who recover from COVID-19 are immune to the disease, and just how beneficial antibodies are.
 
A scientist presents a rapid antibody test for the coronavirus at a lab in Germany last month. Tests like these can show a result in minutes, which could help officials get a better handle on how the disease has spread. But dozens of antibody tests are on the market right now. Doctors say it's difficult to know how accurate they are and where they can be most useful during the crisis.
A scientist presents a rapid antibody test for the coronavirus at a lab in Germany last month. Tests like these can show a result in minutes, which could help officials get a better handle on how the disease has spread. But dozens of antibody tests are on the market right now. Doctors say it's difficult to know how accurate they are and where they can be most useful during the crisis. [ JENS MEYER | Associated Press ]
Published May 1, 2020|Updated May 1, 2020

After testing positive for COVID-19, Dr. Maria Finazzo wanted to help others in Florida who fell ill from the disease.

Finazzo, a radiologist from Sarasota, drove to the Raymond James Stadium testing site in Tampa after she and her husband began displaying symptoms in mid-March. Nearly two weeks later, the results revealed she was positive.

Once she recovered, Finazzo researched how she could donate her antibodies through plasma.

“We had a friend who was very ill and I asked some fellow physicians how I could help,” she said. “I donated plasma at a local blood bank, and it can be used for anyone who is a potential match to my blood type and needs help.”

Antibody tests, which detect signs of infection in blood, have been touted by political leaders as a promising alternative to the more traditional nasal and throat swab tests that have bogged down efforts to fight the virus. Long delays and shortages in collection and swab materials have severely limited the number of people who have been tested so far.

But as antibody tests are slowly being rolled out in labs across Tampa Bay and the nation, doctors say they come with their own set of problems.

Related: Elective surgeries to resume after thousands were postponed in Tampa Bay

“This area is sort of the wild West right now,” said Dr. Kami Kim, a professor of infectious disease at the University of South Florida.

More than 90 antibody tests for COVID-19 are on the market after the Food and Drug Administration loosened restrictions, allowing companies to produce and sell them without being scientifically reviewed.

“When COVID-19 testing first came out, the FDA was too controlled, so they’ve now erred on the other side and have swung too far in the other direction," Kim said. "There are a lot of tests out there and it’s not really clear what the quality of the tests are.”

A man's blood is collected for testing of coronavirus antibodies at a drive-through testing site in Hempstead, N.Y. recently. [SETH WENIG | Associated Press.]

Tampa General Hospital began antibody testing in its laboratory just this week, said Dr. Charles Lockwood, dean of the Morsani College of Medicine at the University of South Florida. The hospital will test all 3,000 of its health care workers this way, hoping to keep them safe by identifying who has been exposed to the virus.

BayCare Health System has also begun to run antibody tests in its labs, said Dr. Nishant Anand, chief medical officer. But it remains unclear how local hospitals will use these tests in the long term.

“The market is flooded with all different companies offering tests, and the accuracy and validity of those tests are not reliable,” Anand said.

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The tests can be used to determine if a person’s immune cells are producing antibodies, which are part of the body’s response to a virus, working to prevent it from spreading. Their presence means a person has been exposed to infection.

But the tests technically cannot diagnose the COVID-19 disease, experts say, because antibodies can come from a variety of coronavirus strains, including the common cold, making the results difficult to discern.

“It’s possible someone can get a false positive,” Kim said. “We still have to work out in what context these tests will be the most useful. Some of these things have not been clarified yet."

However, they can be useful for public health surveillance, data gathering and vaccine development in the long term.

The Infectious Disease Society of America issued a statement last week warning practitioners that there are “there are multiple issues that need to be addressed” for antibody testing, “from test quality to interpretation.”

“The current antibody testing landscape is varied and clinically unverified, and these tests should not be used as the sole test for diagnostic decisions,” the statement said.

Similarly, the World Health Organization cautioned against plans for “immunity passports" that would allow people with COVID-19 antibodies to escape social distancing restrictions. It also discouraged politicians and public health officials from allowing patients who have recovered from the coronavirus to return to work or travel freely.

Antibody tests are generally used to monitor infections like HIV or confirm vaccinations. Blood samples are run in a laboratory to confirm the result, or sometimes, a test result can be read in minutes if it’s a “rapid test," similar to a pregnancy test. Scientists still know too little about the role antibodies play in immunity for the coronavirus, Anand said.

“The biggest value these tests offer right now is from a public health standpoint. It can help us determine how widespread the disease really is,” he said.

Another way BayCare is using antibodies is by taking “convalescent plasma” donations from recovered patients, like Finazzo from Sarasota, and infusing them in ill patients to help them get better, Anand said.

“The first step is really validating an accurate test,” he said. “And the next is determining which method is most beneficial. There is still a lot to be determined."

BayCare will continue to test and monitor the results for now, he added.

In early March, Finazzo and her husband, Michael, had traveled to Denver with their son. When they returned, both she and her husband began to feel sick with a fever and sore throat. Her husband was so sick that he couldn’t get out of bed for a week.

“I remember being surprised, but relieved in a way, once I got the positive test result,” she said. “At least I knew. And I had the ability to help others. It’s very easy to donate plasma.”

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