It can take up to eight days after onset of symptoms for a person’s immune system to develop antibodies, so serological tests are not designed for diagnosing recent or active infections, stated a Mayo Clinic news story. However, Reuters reported that the availability of serological tests is “a potential game changer” because they could identify people who are immune even if they had no symptoms or only mild symptoms.
“Ultimately, this might help us figure out who can get the country back to normal,” Florian Krammer, PhD, told Reuters. Krammer’s lab at the Icahn School of Medicine at Mount Sinai in New York City has developed a serological test. “People who are immune could be the first people to go back to normal life and start everything up again,” he said.
However, some experts advise that the presence of antibodies is not necessarily a “get out of jail free” card when it comes to the coronavirus. “Infectious disease experts say immunity against COVID-19 may last for several months and perhaps a year or more based on their studies of other coronaviruses, including Severe Acute Respiratory Syndrome (SARS), which emerged in 2003,” reported Reuters. “But [the experts] caution that there is no way to know precisely how long immunity would last with COVID-19, and it may vary person to person.”
Additionally, it is also “uncertain whether antibodies would be sufficient protection if a person were to be re-exposed to the virus in very large amounts,” such as in an emergency room or ICU, Reuters reported.
Serological Survey Studies Get Underway Worldwide
Aside from detecting potential immunity, the World Health Organization (WHO) says serological tests could be useful for widespread disease surveillance and epidemiological research.
In the US, the Vitalant
Research Institute is leading several large serological survey or
“serosurvey” studies in which regional blood centers save samples of donated
blood for antibody testing, Science
reported.
Science also reported on a similar WHO initiative in which six countries will pool data from their own antibody studies. And in the Netherlands, blood banks have begun screening thousands of blood donations for presence of antibodies, Wired reported.
FDA Emergency Use Authorization
On March 16, the federal Food and Drug Administration (FDA) announced that it would allow commercial development and distribution of serological tests that “identify antibodies (e.g., IgM, IgG) to SARS-CoV-2 from clinical specimens” without an Emergency Use Authorization (EUA). The agency noted that these tests are “less complex than molecular tests” used to detect active infections, and that the policy change is limited to such testing in medical laboratories or by healthcare workers at the point-of-care. “This policy does not apply to at home testing,” the FDA reiterated.
“Serological tests can play a critical role in the fight against COVID-19 by helping healthcare professionals to identify individuals who have overcome an infection in the past and have developed an immune response,” said FDA Commissioner Stephen M. Hahn, MD (above with President Trump during a Coronavirus Task Force press briefing), in an April 7 press statement. “In the future, this may potentially be used to help determine—together with other clinical data—that such individuals are no longer susceptible to infection and can return to work. In addition, these test results can aid in determining who may donate a part of their blood called convalescent plasma, which may serve as a possible treatment for those who are seriously ill from COVID-19.” (Photo copyright: CNBC.)
FDA Issues First EUA for Rapid Diagnostic Test
Cellex Inc., based in Research Triangle Park, N.C., received the first EUA for its qSARS-CoV-2 serological test on April 1. As with other rapid diagnostic tests (RDTs) under development, the qSARS-CoV-2 test detects the presence of immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in human blood. The biotechnology company’s RDT can be used to test serum, plasma, or whole-blood specimens, stated Cellex, and can produce results in 15 to 20 minutes.
The FDA has authorized use of the antibody test only by laboratories certified under CLIA to perform moderate and high complexity tests. Cellex has set up a COVID-19 website with information about the qSARS-CoV-2 test for clinical laboratories, patients, and healthcare providers.
Other Serological Tests Under Development
Mayo
Clinic Laboratories announced on April 13 that it is ramping up
availability of an internally-developed serological test. “Initial capacity
will be 8,000 tests per day performed at laboratory locations across Mayo Clinic,” stated the announcement.
“Testing will be performed 24 hours a day, and Mayo Clinic Laboratories is working
to ensure turnaround time is as close as possible to 24 hours after receipt of
the sample.”
Emory University in Atlanta announced on April 13 that it will begin deploying its own internally developed antibody test. Initially, testing will be limited to 300 people per day, comprised of Emory Healthcare patients, providers, and staff members. Eventually, testing will be “expanded significantly,” said Emory, with a goal of 5,000 tests per day by mid-June.
RDTs are typically qualitative, meaning they produce a
positive or negative result, stated the Center for Health Security. An ELISA
test “can be qualitative or quantitative,” noted the Center, but it can take
one to five hours to produce results.
A third type of serological test—the neutralization assay—involves infecting a patient’s blood with live coronavirus to determine if antibodies exist that can inhibit growth of the virus. The test takes three to five days in a level 3 biosafety laboratory to produce results. The Straits Times reported on one laboratory in Singapore that developed a neutralization assay to trace the source of COVID-19 infections that originated in Wuhan, China.
Serological testing is another important tool clinical
laboratories and epidemiologists can use to fight and ultimately defeat the
COVID-19 pandemic and is worth watching.
New lab test market could open up if research findings lead Consumer Reports and nine medical specialty associates join forces to target the overuse of certain diagnostic procedures, including some medical laboratory tests
For years, pathologists and physicians have spoken out about the overuse of medical laboratory tests and other diagnostic procedures. Now an interesting alliance of a medical specialty association and Consumer Reports has come together with a highly-publicized plan designed to reduce unnecessary or inappropriate testing by encouraging physicians to more deeply involve patients in the process.
It is the American Board of Internal Medicine Foundation (ABIMF) that is working with Consumer Reports. Their common goal is to stanch the overuse of unnecessary healthcare tests and procedures that do not improve patient outcomes and do run up healthcare costs. Experts estimate the wasteful use of healthcare resources accounts for as much as 30% of current healthcare costs in the United States.
The program is called “Choosing Wisely” (CW). According to a story in Modern Healthcare (MH), “Choosing Wisely” is a campaign to get physicians and patients to discuss whether a particular test is likely to improve patient health or outcome.
Pictured above is the press conference conducted by the American Board of Internal Medicine Foundation (ABIMF) to announce the launch of the “Choosing Wisely” campaign. The goal of this campaign is to reduce overutilization or unnecessary ordering of diagnostic procedures. Each of nine medical specialty associations has put forth a list of specific diagnostic procedures that should be part of this campaign and a number of clinical laboratory tests are on these lists. (Photo copyright by American Society of Nephrology.)
Participating in this initiative are about 375,000 physicians in nine specialty societies. Each of these nine medical specialty groups has identified five diagnostic tests or procedures within their specialty area that warrant re-evaluation by physicians and patients as to whether they will provide useful information or lead to a positive outcome. Clinical laboratory managers and pathologists will be interested to learn that a number of these medical specialty associations have included clinical laboratory tests on their respective lists.
“What we’re asking for is for people to have a conversation,” stated Daniel B. Wolfson, M.H.S.A., ABIM Foundation Executive Vice President and Chief Operating Officer, in the MH story. “These are not rules; they are guidelines used to guide most—but not all—cases,” he explained.
“These societies have shown tremendous leadership in starting a long overdue and important conversation between physicians and patients about what care is really needed,” said Christine K. Cassel, M.D., President and Chief Executive Officer of the ABMF. “Physicians, working together with patients, can help ensure the right care is delivered at the right time for the right patient.” She was quoted in a Choosing Wisely press release.
According to the release, Consumer Reports is working with American Association of Retired People (AARP) and other organizations representing the lay public to get the word out about the “Choosing Wisely” campaign.
Specialist Physicians Identify Some Medical Laboratory Tests for Review
Below are listed the recommendations made by the different medical specialty associations that identify a clinical laboratory test:
Don’t perform unproven diagnostic tests, such as immunoglobulin G (IgG) testing or an indiscriminate battery of immunoglobulin E (IgE) tests, in the evaluation of allergy.
Don’t routinely do diagnostic testing in patients with chronic urticaria.
Don’t recommend replacement immunoglobulin therapy for recurrent infections unless impaired antibody responses to vaccines are demonstrated.
In patients with low pretest probability of venous thromboembolism (VTE), obtain a high-sensitive D-dimer measurement as the initial diagnostic test; don’t obtain imaging studies as the initial diagnostic test.
Don’t perform routine cancer screening for dialysis patients with limited life expectancies without signs or symptoms.
Don’t administer erythropoiesis-stimulating agents (ESAs) to chronic kidney disease (CKD) patients with hemoglobin levels greater than or equal to 10g/dL without symptoms or anemia.
In its coverage of the “Choosing Wisely” initiative, Clinical Laboratory News, a publication of the American Association for Clinical Chemistry, (AACC) reported that the utilization changes CW seeks may sound like bad news for the lab,. But sometimes these types of program can end up promoting appropriate clinical laboratory testing over other options, the writer noted.
The “Choosing Wisely” initiative, at a minimum, does provide another opportunity for pathologists and clinical laboratory managers to add value to physicians and their patients by helping clinicians have confidence they they are ordering the right test at the right time, supported by evidence-based medicine (EBM) guidelines.
