Rapid COVID-19 tests now available in some Maryland doctors’ offices but questions about accuracy persist

Six months into the coronavirus pandemic, testing is moving from mass drive-thru centers and hospitals to doctors’ offices, where the wait time for results is 15 minutes rather than days or longer.

More and faster tests will be a convenience for the public and a boon for officials trying to get a handle on cases, but doctors warn such rapid “point-of-care” tests come with challenges.

“The answer to this pandemic is test, test, test,” said Dr. Ron Elfenbein, medical director and CEO of First Call Medical Center, an urgent care provider in Gambrills. “And we’re having good results. … But these tests aren’t perfect.”

He warns that the kind of rapid test most doctors are likely to offer has a high rate of false negatives. That can undermine efforts to identify those infected with COVID-19, the illness caused by the coronavirus, and isolate them.

That also poses a challenge to state health officials, who have not even decided how to account for these tests. They will be reported but not added to the daily tally from 215 community testing sites provided on the state’s pandemic website, coronavirus.maryland.gov.

Elfenbein said his urgent care center likely has reported more than 1,000 results from rapid tests in the past week alone.

He uses what’s known as an antigen test similar to the tests used to identify other common viral menaces, such as flu and strep, which look for proteins on the surface of the virus. They can miss cases in people tested too soon after exposure, providing false negatives up to 20% of the time.

Until better tests are readily available, Elfenbein’s answer has been to also perform traditional polymerase chain reaction, or PCR, tests. They are a more involved but slower look at the genetic makeup of the virus. The PCR tests are versions of the ones commonly offered at community testing sites, but samples are normally sent to commercial labs that can take days or longer to provide results.

Double testing is not covered by insurance, so few doctors are likely to follow Elfenbein’s lead. But he believes the system ensures both speed and accuracy.

First Call Medical Center is among 122 offices that have been approved so far to offer testing from the Maryland Department of Health since an order last month vastly expanding where tests could be conducted, according to Charles Gischlar, a department spokesman.

The order allowed medical offices with basic lab certification to offer six rapid antigen and PCR tests that have emergency approval from the U.S. Food and Drug Administration.

Many doctors want to offer the tests, but the state moved slower than many others to allow widespread point-of-care testing, said Gene Ransom, CEO of MedChi, an association of Maryland doctors.

“We strongly support it,” he said. “It’ll be helpful, and when used responsibly the tests can be an important tool for public health.”

Most doctors’ offices will offer antigen tests because they already have equipment, Ransom said. The machinery for PCR test analysis can be expensive and in some cases isn’t available because manufacturers can’t keep up with orders.

Some offices, however, are finding they can’t get coronavirus test kits, which include a swab to take a sample and a test strip, which is encased in a cartridge and inserted into an electronic reader.

Dr. Susan Chaitovitz, a pediatrician in Frederick, would like to offer the tests but her supply of test kits is too limited.

“We haven’t gotten enough to be helpful for our clinical patients,” she said. “We’re a large practice and our volume is reasonably high. To roll out, we need a good supply, and the supply we do have has been invaluable to get staff back to work.”

She wants to keep seeking test kits so she has enough for the fall flu season, when many more patients could show up sick. A big factor in her plan, however, is the continued efficiency of community testing sites where she sends patients. They have reduced the time it takes for results to about 48 hours, down from as long as two weeks in late July, which she called “useless.”

The state has been testing 12,000 to more than 20,000 people a day at community sites, with under 5% testing positive for the past month. It’s not clear how many rapid tests are being performed, though doctors already are reporting them to the health department.

Public health experts largely support expanded testing, rejecting recent advice from the U.S. Centers for Disease Control and Prevention that said people who have been exposed to COVID-19 but show no symptoms don’t necessarily need a test.

More testing will find more cases, and that’s critical to controlling the pandemic, said Dr. Yukari Manabe, Johns Hopkins Center for Global Health’s associate director of global health research and innovation.

She said antigen tests were not really designed for asymtompatic cases, and people with a negative result but clearly exposed to the virus by a housemate or someone else should then get a PCR test.

But she said the tests do work well for those with symptoms and she supports their use.

“From a public health standpoint, individuals can get results in 10 minutes or so,” Manabe said, “which is a lot better than waiting seven to 10 days.”

She said testing in doctors’ offices, as well as urgent care centers, pharmacies and elsewhere, will relieve demand on community testing centers that has caused delays in reporting results. Further, she said, manufacturers and other researchers are working on more accurate rapid tests.

Abbott Laboratories, for example, recently won emergency approval for a new test that requires no special equipment. The test strip is affixed to a card, which indicates if someone is positive or negative for COVID-19 in the same way as a pregnancy test.

Abbott says the tests will cost $5 each and the company plans to produce 50 million a month by October.

“The dream is a kid goes to day care and breathes into a tube and in 30 seconds you know he’s positive and he goes home, and everyone inside is negative that day,” Manabe said. “It shouldn’t cost a lot of money, and there is equity in how it’s used; we can’t have a test where only people in the Hamptons can buy them.

“Nothing like that is close,” she added.

Some are working toward that goal, however, including researchers at the University of Maryland, Baltimore County.

The UMBC work is being led by Dipanjan Pan, a professor of chemical, biochemical and environmental engineering. He has created a test that looks at genetic material like a PCR test but is conducted like an antigen test with a test strip. It aims to spot an infection as early as the first day.

Pan said researchers are still working on reducing turnaround times and costs for the system, which can test almost 400 samples at a time, potentially making it ideal for offices, schools or airports that need to screen international travelers. It also could be used at home, Pan said.

In the test, a nasal swab or saliva sample is taken and genetic material extracted. Special molecules attached to ultra-fine particles of gold called nanoparticles are used to detect a protein on the virus. When the molecules find the protein, the nanoparticles cause a chemical agent used in the test to turn blue.

UMBC is in talks with companies to license the test and develop it. Pan, meanwhile, is pursuing emergency approvals from FDA.

“The question is: How do we get to a point where we can expect PCR-level sensitivity, but make it truly a point-of-care test?” he said. “That’s where we are going with this. This kind of approach will be a game-changer.”