COVID-19 antibody tests are coming this week. This
What To Know Antibody Testing for COVID-19
- tests will be widely available
according to https://jamanetwork.com/journals/jama/fullarticle/2764954
In the first such community-wide campaign in the US, the San Miguel County Department of Health offered the voluntary screening to most of the area’s 8000 residents over 2 weeks. Just 8 of the 986 individuals tested on March 26 and 27 were positive for SARS-CoV-2 antibodies. Another 23 were borderline, suggesting that they’d recently been exposed to the virus and were just starting to make antibodies against it. But those were early days. The screenings, paid for by test manufacturer United Biomedical Inc and the county, eventually would be repeated to see how much things had changed.
Unlike polymerase chain reaction (PCR) tests—also referred to as molecular or nucleic acid–based tests—antibody tests aren’t intended to identify active SARS-CoV-2 infections. Instead of detecting viral genetic material in throat or nasal swabs, antibody tests reveal markers of immune response—the IgM and IgG antibodies that for most people show up in blood more than a week after they start to feel sick, when symptoms may already be waning.
Serologic antibody tests not only can confirm suspected cases after the fact, they can also reveal who was infected and didn’t know it. Up to a quarter of people with SARS-CoV-2 infection may unwittingly spread the virus because they have mild or no symptoms.
Implications for the health care workforce could be substantial, microbiologist Florian Krammer, PhD, of Mount Sinai’s Icahn School of Medicine, said in an interview. “If we find serologically that you are immune, it’s very unlikely that you can get reinfected, which means you can’t pass the virus on to your colleagues or to other patients. And I think it also gives a peace of mind if you have to work with COVID-19 patients to know that you’re probably immune to the infection,” he explained.
Antibody tests are ramping up quickly, with a growing list of commercial kits and test protocols from academic researchers including Krammer’s team and a Dutch team coming online in recent days and weeks. Scientists said the tests will be critical in the weeks and months ahead, when they may be used for disease surveillance, therapeutics, return-to-work screenings, and more. But the tests must be deployed appropriately, they added, and with an acknowledgment of unanswered questions.
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The FDA and CDC say
“The U.S. Food and Drug Administration (FDA) recommends that health care providers continue to use serological tests intended to detect antibodies to SARS-CoV-2 to help identify people who may have been exposed to the SARS-CoV-2 virus or have recovered from the COVID-19 infection. Health care providers should also be aware of the limitations of these tests and the risks to patients and the community if the test results are used as the sole basis to diagnose COVID-19.
The FDA is not aware of an antibody test that has been validated for diagnosis of SARS-CoV-2 infection. While the FDA remains open to receiving submissions for these tests for such uses, based on the underlying scientific principles of antibody tests, the FDA does not expect that an antibody test can be shown to definitively diagnose or exclude SARS-CoV-2 infection.
The FDA recommends health care providers:
- Continue to use serological (antibody) tests, as appropriate, and be aware of their limitations.
- Do not use serological (antibody) tests as the sole basis to diagnose COVID-19 but instead as information about whether a person may have been exposed.
- Be aware that not all marketed serological tests have been evaluated by the FDA. The FDA’s authorized tests, including serological tests, are listed on the Emergency Use Authorization (EUA) page. Tests being offered under a policy outlined in the FDA’s COVID-19 Diagnostic Policy Guidance are listed on our FAQ page. Such tests have not been reviewed by the FDA, unless an EUA has also been submitted and reviewed by FDA.
Serological tests detect antibodies present in the blood when the body is responding to a specific infection, like COVID-19. They detect the body’s immune response to the infection caused by the virus rather than detecting the virus itself. Experience with other viruses suggests that individuals whose blood contains antibodies associated with SARS-CoV-2 infection—provided they are recovered and not currently infected with the virus—may be able to resume work and other daily activities in society. They may also be eligible to serve as potential donors of convalescent plasma.
In the early days of an infection, when the body’s immune response is still building, antibodies may not be present in detectable levels. This limits the test’s effectiveness for diagnosing COVID-19 and is why it should not be used as the sole basis to diagnose COVID-19. Currently authorized serological tests for SARS-CoV-2 measure IgM and/or IgG antibodies. Since IgM antibodies may not develop early, or at all, in infected patients, this type of antibody test is not used to rule out SARS-CoV-2 in an individual. Since IgG antibodies generally do not develop until later, this type of antibody test, even though it is more specific to SARS-CoV-2, is not used to rule-out SARS-CoV-2 infection in an individual. We also do not know how long IgM or IgG antibodies to SARS-CoV-2 will remain present in the body after the infection has been cleared.
While antibody tests by themselves are of limited value in the immediate diagnosis of a patient where COVID-19 infection is suspected, using this type of test on many patients may help the medical community better understand how the immune response against the SARS-CoV-2 virus develops in patients over time and how many people may have been infected. While there is a lot of uncertainty with this new virus, it is also possible that, over time, broad use of antibody tests and clinical follow-up will provide the medical community with more information on whether or not and how long a person who has recovered from the virus is at lower risk of infection if they are exposed to the virus again.
Serological tests can play a critical role in the fight against COVID-19 by helping health care professionals identify individuals who may have been exposed to SARS-CoV-2 virus and may have developed an immune response. In the future, this may potentially be used to help determine, together with other clinical data, whether these individuals are less susceptible to infection.
Serological test results may also aid in determining who may qualify to donate blood that can be used to manufacture convalescent plasma as a possible treatment for those who are seriously ill from COVID-19.
Under the FDA’s March 16 policy for serological tests, the FDA provided regulatory flexibility for developers offering such tests without FDA review and without an EUA where they have notified FDA that they have validated their tests and provide disclaimers about the limitations of the tests with any results generated by their tests, as outlined in the policy. The FDA does not review the validation, or accuracy, data for these tests unless an EUA is submitted. Test for which developers have provided a notification are listed on the FDA’s COVID-19 Diagnostics FAQ page.
Serological test developers may pursue an EUA by submitting information about their test, including their validation data, to the FDA for review. Tests that are issued an EUA are listed on the FDA’s EUA web page.
To help ensure that health care providers have access to accurate tests, the FDA is working with the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC) on a validation projectExternal Link Disclaimer to help identify the most promising serological tests. This validation project is ongoing, and we hope to have additional information to share in the future.
The FDA will continue to keep health care providers and the public informed if new or additional information becomes available.
Reporting Problems to the FDA
Some firms are falsely claiming that their serological tests are FDA approved or authorized, or falsely claiming that these tests can diagnose COVID-19. The FDA will take appropriate action against firms making false claims or marketing tests that are not accurate and reliable.
In addition, the FDA encourages health care providers to report any adverse events or suspected adverse events experienced with serological tests.
- Voluntary reports can be submitted through MedWatch, the FDA Safety Information and Adverse Event Reporting program.
- Device manufacturers and user facilities must comply with any applicable Medical Device Reporting (MDR) regulations.
- Health care personnel employed by facilities that are subject to the FDA’s user facility reporting requirements should follow the reporting procedures established by their facilities.
- The sale of fraudulent COVID-19 products is a threat to the public health. Consumers and health care professionals can help by reporting suspected fraud to the FDA’s Health Fraud Program or the Office of Criminal Investigations. You can also email FDA-COVID-19-Fraudulent-Products@fda.hhs.gov
Prompt reporting of adverse events can help the FDA identify and better understand the risks associated with medical devices.“”
Antibody, or serological, tests are designed to identify people who may have overcome covid-19, including those who had no symptoms, and developed an immune response. They are not designed to detect active infections. Some officials tout the blood tests as a way to reopen the economy by identifying individuals who have developed immunity and can safely return to work. But many scientists, as well as the World Health Organization, say evidence is lacking that even high-quality antibody tests can prove someone has immunity from the novel coronavirus and is not at risk of being reinfected.
The emergence of dozens of tests never reviewed by the FDA — many of which are being aggressively marketed — could confuse doctors, hospitals, employers and consumers clamoring for the products, according to critics who say the agency’s oversight of the tests has been lax. The questions are taking on special importance as federal and state officials debate strategies, including using serological testing, to help determine when they can end state and local lockdowns.
“A test is only as good as its results,” said Kelly Wroblewski, director of infectious disease programs at the Association of Public Health Laboratories, which has been urging the FDA to take a closer look at the unapproved tests. “Having many inaccurate tests is worse than having no tests at all.”
Prodded by such concerns, the FDA recently stepped up warnings and is joining other agencies, including the National Cancer Institute, to try to determine whether the unvetted tests actually work.
On Thursday, during an interview with Washington Post Live, FDA Commissioner Stephen Hahn said “people should be very cautious” about tests that have not undergone the rigorous process of getting emergency use authorization from the agency. The FDA over the weekend said four tests have gotten such authorizations: Cellex, Chembio Diagnostic Systems, Ortho Clinical Diagnostics and Mount Sinai Laboratory.
Much of the work validating the unauthorized tests will be done by the National Cancer Institute, working with the Centers for Disease Control and Prevention, the National Institute of Allergy and Infectious Diseases and academic laboratories. The cancer institute will use its human papillomavirus (HPV) serology testing lab at Frederick National Laboratory for the work. The assessments also will be conducted for some tests seeking FDA emergency use authorization, said Hahn in a statement Saturday evening. The goal is to have “greater confidence in test performance,” he said.
Meanwhile, the unreviewed tests remain on the market. In mid-March, the FDA, wanting to ensure quick access to serological tests, said manufacturers could sell them after validating results themselves and simply notifying the agency. The labels on the products must state they aren’t FDA-approved or meant to be used as the sole basis for diagnosing active infections. The agency lists on its website the companies and laboratories that have submitted those notifications. In response to concerns the list might be seen as an endorsement, the agency updated its website to make clear which tests are authorized by the FDA and which aren’t, Hahn said.
Testing experts warn the risks of inaccurate tests are high. A wrong result could, for example, indicate individuals have immunity against the virus when they don’t, potentially resulting in behavior that would endanger themselves and their families. The peril of buying unvetted tests was underscored by the British government’s recent $20 million purchase of antibody tests from China that didn’t work. Even for high-quality tests, scientists say, they don’t know the level of antibodies needed to make someone immune from the virus or how long protection might last.
Many of the unreviewed tests being sold in the United States are made in China or elsewhere in Asia. Distributors staunchly defend their products as a way to accelerate testing in a country that has been hobbled by shortages and to provide individuals, employers and governments with critical information.
Jonathan Cohen, president and chief executive of 20/20 GeneSystems, based in Rockville, Md., said the test he is selling to medical professionals and clinical laboratories, named “CoronaCheck,” has been approved by the Chinese equivalent of the FDA and verified by hospitals in the United States. “These tests are quite good,” he said.
Paul Kahlert, owner and president of ARCpoint Labs of Edina, Minn., said customers are eager to know whether they were infected and also whether they may be able to donate blood that can be used to manufacture “convalescent plasma,” which is being tried as a potential treatment for people with covid-19. “People are so appreciative we are doing this,” he said. “They want to help.”
But an information sheet about the ARCpoint antibody tests raises concerns, said Scott Becker, executive director of the Association of Public Health Laboratories. The sheet said the presence of certain antibodies suggests a person has “functional immunity” and can “discontinue social distancing.” Becker said scientists don’t know enough to say that about antibody tests for the coronavirus.
Amanda Harley, a spokeswoman for ARCpoint Labs, a franchise based in Greenville, S.C., said the information sheet was created as a guide for franchisees and is no longer used. John Constantine, the company’s president and chief executive, said the firm also provides disclaimers about its product, such as that test results are not a guarantee of immunity. “We would never say, ‘You are good. Go see grandma without a mask,’” he said.
The agency’s willingness to allow tests on the market without review means “you are getting a lot of folks where this isn’t their core competence entering the market, and there is an opportunity for flawed results in that environment,” said David Morgan, head of transplant and infectious disease at Eurofins U.S. A subsidiary, Boston Heart Diagnostics, is offering an antibody test to hospitals and is seeking FDA authorization, company officials said.
Antibody tests typically come in either rapid versions that use a small amount of blood from a finger prick and may cost as little as $20 or less, or others that rely on traditional blood draws and cost considerably more. Many of the finger-prick ones are being marketed for use in doctors’ offices and pharmacies, even though the government requires all unauthorized tests be run in CLIA laboratories certified to conduct high complexity testing, Becker said.
That requirement is slowing use of the antibody tests, say suppliers who argue doctors should be able to run point-of-care tests in their offices without using sophisticated labs.
Some state and local health departments also have warned consumers and doctors to avoid tests that haven’t been authorized. In San Diego County, officials shut down a pop-up antibody testing site at a community college, citing a lack of documentation about the test.
Some unreviewed tests have been developed by high-quality academic medical centers and aren’t a source of concern among public health experts. Emory University School of Medicine, for example, created a test it is planning to use for staff and patients to see how broadly the virus has been transmitted in its community.
Marybeth Sexton, an Emory infectious disease specialist, got the test because she wondered if a bout of illness in February was caused by the coronavirus. The test detected antibodies to the virus, but because she is still uncertain whether she’s immune, she plans to continue social distancing and wearing a mask. “I won’t do anything different,” she said.
In New York City, periodontist Scott Froum said he is exploring offering antibody tests to staff and patients when he reopens for routine care as an extra layer of protection against the virus. But he’s wrestling with regulations and choices. “You have to be careful,” he said. “Some of the tests don’t look kosher.”
The FDA is expected to authorize more tests in coming days and weeks. To get the volume of serology testing the nation needs, officials say, more big manufacturers and laboratories will have to get involved. One big manufacturer, Abbott, launched a serology test and plans to produce 20 million tests a month by June. The company said it will apply to FDA for official authorization.
Carolyn Y. Johnson contributed to this report.