Facing a backlog, the state’s public health laboratory turned to the medical laboratory at Dartmouth Hitchcock Medical Center
Much of the attention surrounding the COVID-19
outbreak—the illness caused by the SARS-CoV-2
coronavirus—has focused on large urban areas such as New York City and Los
Angeles. However, the virus is impacting many rural areas as well. This is true
in New Hampshire, where the diagnostic response required close cooperation
between the state’s public health
laboratory and the clinical
laboratory at its lone academic medical center. Their experience offers
lessons for medical
laboratory leaders nationwide.
“When these things happen and you surge beyond what you
could imagine, it’s the relationships with people that matter more than
anything,” said Christine
L. Bean, PhD, Administrator of New
Hampshire Public Health Laboratory Division of Public Health Services , Concord,
N.H., during a recent Dark
Daily webinar, titled, “What Hospital and Health System Labs Need to
Know About Operational Support and Logistics During the COVID-19 Outbreak.”
As Bean explained, during the earliest stages of the
pandemic the “CDC was doing the testing” and the state lab’s role was limited
to submitting samples from patients deemed as “presumptive positives.” Then, on
Feb. 4, the FDA granted an emergency
use authorization (EUA) allowing use of the CDC-developed real-time
reverse transcriptase PCR (RT-PCR) assay by designated labs.
The New Hampshire Public Health Laboratory (NHPHL) received
its first test kit on Feb. 10, Bean said. But the kits were recalled due to
validation problems with one of the reagents. On Feb. 26, the CDC
issued revised test instructions allowing use of the test without the N3
primer and probe set that had caused the early validation issues. The NHPHL
verified the test under the new guidelines and went live on March 2, she said.
However, with a capacity of 150 to 200 tests per day, the
lab wasn’t equipped to handle a large volume. “Much of what we do is really
population-based,” she said. “Most of the time we’re not doing patient
diagnostic testing.”
Christine L. Bean, PhD (left), Administrator of the New Hampshire Public Health Laboratory, and Joel Lefferts, PhD (right), Assistant Professor of Pathology and Laboratory Medicine, and Assistant Director of the Molecular Pathology, at Dartmouth’s Geisel School of Medicine, spoke with Dark Daily’s Editor-in-Chief Robert Michel during a webinar on what hospital and health system labs need to know about operational support and logistics during the COVID-19 outbreak. The webinar can be freely downloaded by clicking here. (Photo copyright: Dark Daily.)
NHPHL Turns to the Medical Laboratory at DHMC-CGHT for
Help
The DHMC-CGHT lab began having its own discussions about
testing in the first week of February, said Joel
A. Lefferts, PhD, HCLD, DABCC, Assistant Professor of Pathology and
Laboratory Medicine and Assistant Director of Molecular Pathology at
Dartmouth’s Geisel School of
Medicine. They were unsure of how much need there would be, but “throughout
the month of February, we started exploring different testing options,” he said
during the Dark Daily webinar.
The Dartmouth-Hitchcock lab team began with the CDC test. However,
Lefferts noted that the initial FDA guidance was “somewhat restrictive” and required
specific RNA extraction
kits and real-time PCR instruments. “If our lab didn’t have the capability to
perform everything exactly as indicated, we would be running it off-label and
would have to possibly submit our own EUA submission to the FDA,” he explained.
Later, though, the FDA and CDC loosened those restrictions and the lab began testing with the CDC assay on March 18, using a Thermo Fisher ABI 7500Dx instrument, Lefferts said. According to Thermo Fisher’s website, the ABI 7500Dx “is a real-time nucleic acid amplification and five-color fluorescence detection system available for in vitro diagnostic use.”
However, Lefferts continued, “we only had one of these
7500Dx instruments, and it was a relatively manual and labor-intensive
process.” It allowed a maximum of 29 samples per run, he said, and took about
five hours to produce results.
Then, the FDA granted an EUA for Abbott’s
m2000 assay, which runs on the company’s m2000rt real-time PCR instrument.
“We were really excited, because we happened to have two of these systems in
our lab,” he said. “We quickly got on the phone and ordered some of these
kits.”
The DHMC-CGHT lab went live with the new system on March 23.
It can handle up to 94 samples per run, said Lefferts, and with two instruments
running from 6 a.m. to 9 p.m., “there’s a potential to do as many as 10 runs
per day.”
This was the system they used to help New Hampshire’s Public
Health Lab with its backlog. “It was unbelievable to see that our backlog could
be really wiped out,” said Bean.
Challenges for Medical Labs
Gearing up for testing in a public health emergency poses
many challenges, Lefferts advised. “You need to look at what instrumentation
you have in your laboratory, what the experience level of your lab team is, how
much space you have, your expected batch size, and your needed turnaround
time.”
The two labs also had to deal with regulatory uncertainty. “This EUA process is something for which we don’t have much experience,” he said. “Trying to juggle CLIA, CAP, the FDA, and possibly state regulations is a bit challenging. You definitely need to do your research and talk to other clinical laboratories that are doing this testing to get advice.”
Lefferts explained that the most significant challenges to
develop and validate a molecular assay for COVID-19 included:
Availability of validation materials.
Obtaining “positive [viral] samples may be a challenge, depending on where you
are and what you have access to,” said Lefferts. However, he credits the FDA
for being “very proactive” in suggesting alternative sources for “viral isolates or genomic RNA that’s been
extracted from some of these viral isolates.”
Availability of collection kits. “We can
do a lot more testing now,” he said, but one bottleneck is the limited
availability of supplies such as nasopharyngeal swabs
and viral transport media. “We’re looking at alternative collection options,”
he said, such as 3D-printed swabs or even Q-tips [household cotton swabs], though
“hopefully it won’t come to that.” The DHMC-CGHT lab also considered producing its
own transport media.
Turnaround times. “Our lab wants to get
those results out as soon as possible,” Lefferts said. “So, we’re looking at
alternative methods to get that testing out sooner.” For example, “do we just
do the SARS-CoV-2 testing on a patient, or do we need to do other influenza and other viral
pathogens,” while also keeping up with other routine testing during the
pandemic?
Staffing issues. “Fatigue is a big issue
with members of our labs who put in lots of extra hours,” he said. The
DHMC-CGHT lab has developed contingency plans in case lab personnel get sick.
This critical information will be highly useful for
Laboratory Directors and Managers, Laboratory Supervisors and Team Leaders,
Integrated Health System Leaders, Hospital Group Leaders, Physicians and
Physician Group Leaders, Phlebotomy Managers, Courier and Logistics Managers,
and Safety and Compliance Managers.
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.
Media reports in the United Kingdom cite bad timing and centralization of public health laboratories as reasons the UK is struggling to meet testing goals
Clinical pathologists and medical laboratories in UK and the US function within radically different healthcare systems. However, both countries faced similar problems deploying widespread diagnostic testing for SARS-CoV-2, the novel coronavirus that causes COVID-19. And the differences between America’s private healthcare system and the UK’s government-run, single-payer system are exacerbating the UK’s difficulties expanding coronavirus testing to its citizens.
The Dark Daily reported in March that a manufacturing snafu had delayed distribution of a CDC-developed diagnostic test to public health laboratories. This meant virtually all testing had to be performed at the CDC, which further slowed testing. Only later that month was the US able to significantly ramp up its testing capacity, according to data from the COVID Tracking Project.
However, the UK has fared even worse, trailing Germany, the US, and other countries, according to reports in Buzzfeed and other media outlets. On March 11, the UK government established a goal of administering 10,000 COVID-19 tests per day by late March, but fell far short of that mark, The Guardian reported. The UK government now aims to increase this to 25,000 tests per day by late April.
This compares with about 70,000 COVID-19 tests per day in
Germany, the Guardian reported, and about 130,000 per day in the US
(between March 26 and April 14), according to the COVID Tracking Project.
“Ministers need to explain why the NHS [National Health Service] is not testing to capacity, why we are falling behind other countries, and what measures they will put in place to address this situation as a matter of urgency,” MP Keir Starmer (above) said in Parliament in late March, The Guardian reported. (Photo copyright: The Guardian.)
What’s Behind the UK’s Lackluster COVID-19 Testing
Response
In January, when the outbreak first hit, Public Health England (PHE) “began a strict program of contact tracing and testing potential cases,” Buzzfeed reported. But due to limited medical laboratory capacity and low supplies of COVID-19 test kits, the government changed course and de-emphasized testing, instead focusing on increased ICU and ventilator capacity. (Scotland, Wales, and Northern Ireland each have separate public health agencies and national health services.)
Later, when the need for more COVID-19 testing became
apparent, UK pathology laboratories had to contend with global shortages of
testing kits and chemicals, The Guardian reported. At present, COVID-19 testing
is limited to healthcare workers and patients displaying symptoms of pneumonia,
acute
respiratory distress syndrome, or influenza-like illness, PHE stated in “COVID-19:
Investigation and Initial Clinical Management of Possible Cases” guidance.
Another factor that has limited widespread COVID-19 testing is the country’s highly-centralized system of public health laboratories, Buzzfeed reported. “This has limited its ability to scale and process results at the same speed as other countries, despite its efforts to ramp up capacity,” Buzzfeed reported. Public Health England, which initially performed COVID-19 testing at one lab, has expanded to 12 labs. NHS laboratories also are testing for the SARS-CoV-2 coronavirus, PHE stated in “COVID-19: How to Arrange Laboratory Testing” guidance.
Sharon Peacock, PhD, PHE’s National Infection Service Interim Director, Professor of Public Health and Microbiology at the University of Cambridge, and honorary consultant microbiologist at the Cambridge clinical and public health laboratory based at Addenbrookes Hospital, defended this approach at a March hearing of the Science and Technology Committee (Commons) in Parliament.
“Laboratories in this country have largely been merged, so we have a smaller number of larger [medical] laboratories,” she said. “The alternative is to have a single large testing site. From my perspective, it is more efficient to have a bigger testing site than dissipating our efforts into a lot of laboratories around the country.”
Writing in The Guardian, Paul Hunter, MB ChB MD, a microbiologist and Professor of Medicine at University of East Anglia, cites historic factors behind the testing issue. The public health labs, he explained, were established in 1946 as part of the National Health Service. At the time, they were part of the country’s defense against bacteriological warfare. They became part of the UK’s Health Protection Agency (now PHE) in 2003. “Many of the laboratories in the old network were shut down, taken over by local hospitals or merged into a smaller number of regional laboratories,” he wrote.
US Facing Different Clinical Laboratory Testing Problems
Meanwhile, a few medical laboratories in the US are now contending with a different problem: Unused testing capacity, Nature reported. For example, the Broad Institute of MIT and Harvard in Cambridge, Mass., can run up to 2,000 tests per day, “but we aren’t doing that many,” Stacey Gabriel, PhD, a human geneticist and Senior Director of the Genomics Platform at the Broad Institute, told Nature. Factors include supply shortages and incompatibility between electronic health record (EHR) systems at hospitals and academic labs, Nature reported.
Politico
cited the CDC’s narrow testing criteria, and a lack of supplies for collecting
and analyzing patient samples—such as swabs and personal protective equipment—as
reasons for the slowdown in testing at some clinical laboratories in the US.
Challenges Deploying Antibody Tests in UK
The UK has also had problems deploying serology tests designed to detect whether people have developed antibodies against the virus. In late March, Peacock told members of Parliament that at-home test kits for COVID-19 would be available to the public through Amazon and retail pharmacy chains, the Independent reported. And, Politico reported that the government had ordered 3.5 million at-home test kits for COVID-19.
However, researchers at the University of Oxford who had been charged with validating the accuracy of the kits, reported on April 5 that the tests had not performed well and did not meet criteria established by the UK Medicines and Healthcare products Regulatory Agency (MHRA). “We see many false negatives (tests where no antibody is detected despite the fact we know it is there), and we also see false positives,” wrote Professor Sir John Bell, GBE, FRS, Professor of Medicine at the university, in a blog post. No test [for COVID-19], he wrote, “has been acclaimed by health authorities as having the necessary characteristics for screening people accurately for protective immunity.”
He added that it would be “at least a month” before suppliers could develop an acceptable COVID-19 test.
In the United States, the Cellex COVID-19 test is intended for use by medical laboratories. As well, many research sites, academic medical centers, clinical laboratories, and in vitro diagnostics (IVD) companies in the US are working to develop and validate serological tests for COVID-19.
Within weeks, it is expected that a growing number of such
tests will qualify for a Food and Drug Administration (FDA) Emergency Use
Authorization (EUA) and become available for use in patient care.
Bioeasy stands behind the accuracy of its coronavirus test kits and, in a statement, questioned whether they were being used correctly
How accurate are the SARS-CoV-2 test kits being offered by different in vitro diagnostics companies, as well as the internally-developed COVID-19 tests developed by individual medical laboratories, both here in the United States and in other countries? It’s a question that has not been addressed by the news media nor by healthcare regulators.
That
is why a recent news story reported complaints by authorities in several
European countries that COVID-19 tests they had purchased were “unreliable.”
The source of the COVID-19 test kits was a Chinese company.
On Wednesday, government officials in China announced that manufacturers of test kits for SARS-CoV-2, the novel coronavirus that causes the COVID-19 illness, can no longer export their tests unless China’s National Medical Products Administration (NMPA) has licensed and registered those tests, the South China Morning Post (SCMP) reported.
China issued the new rules after receiving complaints from buyers in Europe about the quality and accuracy of tests kits and other products, including personal protective equipment (PPE), ventilators, and infrared thermometers, SCMP wrote. Previously, Chinese exporters were required only to have CE certification to indicate that their goods conformed to the health and safety standards required for sale in the European Economic Area, SCMP added.
In a joint statement issued March 31, China’s Ministry of Commerce, General Administration of Customs (GAC), and the National Medical Products Administration said the new rule applies to all companies seeking to export test kits, face masks, protective clothing, ventilators, and infrared thermometers.
Spain
Discontinues Use of Rapid Diagnostic Tests from Bioeasy
The new rules came after health authorities in Spain stopped using a rapid diagnostic test (RDT) kit that required a nasopharyngeal (NP) swab to collect specimens to diagnose patients for the SARS-CoV-2 virus, saying the test kits from Shenzhen Bioeasy Biotechnology were unreliable. Turkey also rejected the Shenzen Bioeasy test kits after finding similar problems, according to The Middle East Eye. Ukraine and Georgia also bought kits from Bioeasy, according to published reports.
The low accuracy rate of the Bioeasy coronavirus test kits raises questions about the rapid rate of development for new tests in the United States and worldwide, said Michael Noble, MD, FRCPC, Chair of the University of British Columbia (UBC) Clinical Microbiology Proficiency Testing program and the UBC Program Office for Laboratory Quality Management, in Vancouver.
“There’s
an inherent problem with building a test during a crisis,” Noble said in an
interview with Dark Daily. “Clinical laboratory test developers are
being forced into building tests in a hurry, and the highest likelihood is that
they will fail because these tests take a lot of time if the aim is to get them
right.
“When
a company or a lab feels the need to go too fast, it is likely to take
shortcuts,” he added. “And every time a shortcut is taken, an opportunity for
error is created.
“Also,
the federal Food and Drug Administration (FDA) may be going too fast to issue
emergency use authorizations (EUAs). If laboratory test developers and the FDA
go too fast, then both could make mistakes,” Noble noted.
“The lesson for labs in the United States and everywhere is you can’t go too fast and you don’t want to go too slow either,” Michael Noble, MD (above), Chair of the University of British Columbia Clinical Microbiology Proficiency Testing Program, told Dark Daily. “Instead, you need to proceed as quickly as you can, but also take as long as you need to ensure you follow all the steps accurately.” (Photo copyright: The Dark Report.)
Bioeasy
Questions Whether Tests are Being Used Correctly
On
March 27, SCMP reported that Shenzhen Bioeasy would send new kits to
ensure that “patients get the best diagnostics” and to “ensure the test kits’
sensitivity and specificity.” The company also raised questions about whether
the tests were used properly and promised to send a video explaining how those
administering the tests should collect specimens using NP swabs.
“As
it [is a] rapid test kit, following the protocol is very important,” the
company added, according to SCMP.
Last
week, Zhu Hai, a manager at
Shenzen Bioeasy, said reports that the test kits had a low accuracy rate were
untrue, SCMP reported. A more detailed explanation would be given via
official Chinese government channels, he added.
Shenzen
Bioeasy also issued a statement about the tests, saying, “The production export
of our CE products to Spain has been done according [to] regulations. All
Bioeasy COVID-19 rapid test [kits] are officially CE-IVD approved, so we are free
to [export] and sell in [the EU],” SCMP reported.
The company exported 337,000 tests to South Korea and more than 420,000 test kits to at least 10 countries, including Italy, Qatar, and Ukraine, the company added. It had five million such kits under production, the company said.
Spain
Purchased More than Half a Million Bioeasy Test Kits
One
of the first publications to report the inaccuracy problems was El País, a Spanish
language daily newspaper in Madrid.
The
Shenzen Bioeasy tests functioned much like pregnancy tests, the newspaper
wrote. Once the sample is taken, the NP swab is diluted and placed into a
cartridge with a lined test strip showing whether the result is positive,
negative, or invalid. “The tests detect the presence of antigen and the result is obtained in 10
or 15 minutes,” El País wrote.
Based
in part on a claim that the medical laboratory test kits have an 80% accuracy
rate, the government purchased 640,000 kits to screen health workers and the
elderly. If the Chinese tests were of sufficient quality, negative or doubtful
results would require a confirmatory molecular diagnostics test, the
newspaper added.
The
Chinese embassy in Spain also responded, saying on Twitter on March 26 that
the country’s National Medical Products Administration had not approved the
tests, and that they were not included in the medical supplies the Chinese
government sent to Spain, SCMP reported. “The Chinese Ministry of
Commerce offered Spain a list of approved suppliers, in which Shenzhen Bioeasy
Biotechnology was not included,” the embassy added.
After
the low accuracy rates were reported, the Spanish government said it ordered
€432 million (US$468 million) worth of medical supplies from China, 5.5 million
test kits, 550 million face masks, and 950 ventilators, SCMP added. But
none of the kits in this order were from Shenzen Bioeasy, the government said.
SCMP quoted Professor Leo Poon
Lit-man, BSc, MPhil, DPhil, FFPH, an expert in the SARS-CoV-2 coronavirus
who helped design a testing protocol for the COVID-19 illness, and who is a
Professor and Division Head of the Division of Public Health Laboratory
Sciences at The University of Hong Kong. A claim of 80% accuracy
for a test using nasal swabs was perplexing, because such tests are known to be
inaccurate, Poon said. “It would be dangerous if it’s used on a large scale,
since patients who are supposed to be positive might not be detected,” he
added.
Pathologists
and clinical laboratory scientists know there are many reasons why a clinical
laboratory test can be unreliable or inaccurate. For example, during the
production of a batch of tests, one step in the manufacturing process may have
gone awry and that problem was not detected before those tests were shipped to
a medical laboratory.
Unfortunately,
when lab tests are proved to be “unreliable” or inaccurate, the public or the
medical laboratory profession seldom learn the reasons for these problems and
what steps were taken to resolve them.
At present, medical laboratories are collecting blood specimens for testing by authorized public health labs. However, clinical laboratories should prepare for the likelihood they will be called on to perform the testing using the CDC test or other tests under development.
“We need to be vigilant and understand everything related to the testing and the virus,” said Bodhraj Acharya, PhD, Manager of Chemistry and Referral Testing at the Laboratory Alliance of Central New York, in an exclusive interview with Dark Daily. “If the situation comes that you have to do the testing, you have to be ready for it.”
The current criteria for determining PUIs include clinical features, such as fever or signs of lower respiratory illness, combined with epidemiological risks, such as recent travel to China or close contact with a laboratory-confirmed COVID-19 patient. The CDC notes that “criteria are subject to change as additional information becomes available” and advises healthcare providers to consult with state or local health departments if they believe a patient meets the criteria.
Bodhraj Acharya, PhD (above), is Manager of Chemistry and Referral Testing at the Laboratory Alliance of Central New York. In an exclusive interview with Dark Daily, he stressed the importance that medical laboratories be prepared. “We need to be vigilant and be active and understand everything related to this virus and the testing. That’s the role of clinical laboratory scientists, to be ready because this can become a pandemic anytime. It can spread and tomorrow the CDC could announce it is disseminating the test to designated laboratories.” (Photo copyright: Laboratory Alliance of Central New York.)
Test Kit Problems Delay Diagnoses
On Feb. 4, the FDA issued a Novel Coronavirus Emergency Use Authorization (EUA) allowing state and city public health laboratories, as well as Department of Defense (DoD) labs, to perform presumptive qualitative testing using the Real-Time Reverse Transcriptase PCR (RT-PCR) diagnostic panel developed by the CDC. Two days later, the CDC began distributing the test kits, a CDC statement announced. Each kit could test 700 to 800 patients, the CDC said, and could provide results from respiratory specimens in four hours.
However, on Feb. 12, the agency revealed in a telebriefing that manufacturing problems with one of the reagents had caused state laboratories to get “inconclusive laboratory results” when performing the test.
“When the state receives these test kits, their procedure is to do quality control themselves in their own laboratories,” said Nancy Messonnier, MD, Director of the CDC National Center for Immunization and Respiratory Diseases (NCIRD), during the telebriefing. “Again, that is part of the normal procedures, but in doing it, some of the states identified some inconclusive laboratory results. We are working closely with them to correct the issues and as we’ve said all along, speed is important, but equally or more important in this situation is making sure that the laboratory results are correct.”
During a follow-up telebriefing on Feb. 14, Messonnier said
that the CDC “is reformulating those reagents, and we are moving quickly to get
those back out to our labs at the state and local public health labs.”
Above is a picture of CDC’s laboratory test kit for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). CDC is shipping the test kits to laboratories CDC has designated as qualified, including US state and local public health laboratories, Department of Defense (DOD) laboratories, and select international laboratories. The test kits are bolstering global laboratory capacity for detecting SARS-CoV-2. (Photo and caption copyright: Centers for Disease Control and Prevention.)
Serologic Test Under Development
The current test has to be performed after a patient shows
symptoms. The “outer bound” of the virus’ incubation period is 14 days, meaning
“we expect someone who is infected to have symptoms some time during those 14
days,” Messonnier said. Testing too early could “produce a negative result,”
she continued, because “the virus hasn’t established itself sufficiently in the
system to be detected.”
Messonnier added that the agency plans to develop a serologic test that will identify people who were exposed to the virus and developed an immune response without getting sick. This will help determine how widespread it is and whether people are “seroconverting,” she said. To formulate this test, “we need to wait to draw specimens from US patients over a period of time. Once they have all of the appropriate specimens collected, I understand that it’s a matter of several weeks” before the serologic test will be ready, she concluded.
“Based on what we know now, we believe this virus spreads
mainly from person to person among close contacts, which is defined [as] about
six feet,” Messonnier said at the follow-up telebriefing. Transmission is
primarily “through respiratory droplets produced when an infected person coughs
or sneezes. People are thought to be the most contagious when they’re most
symptomatic. That’s when they’re the sickest.” However, “some spread may happen
before people show symptoms,” she said.
The virus can also spread when people touch contaminated surfaces and then touch their eyes, nose, or mouth. But it “does not last long on surfaces,” she said.
Where the Infection Began
SARS-CoV-2 was first identified during an outbreak in Wuhan, China, in December 2019. Soon thereafter, hospitals in the region “were overwhelmed” with cases of pneumonia, Dr. Acharya explained, but authorities could not trace the disease to a known pathogen. “Every time a new pathogen originates, or a current pathogen mutates into a new form, there are no molecular tests available to diagnose it,” he said.
So, genetic laboratories used next-generation sequencing, specifically unbiased nontargeted metagenomic RNA sequencing (UMERS), followed by phylogenetic analysis of nucleic acids derived from the hosts. “This approach does not require a prior knowledge of the expected pathogen,” Dr. Acharya explained. Instead, by understanding the virus’ genetic makeup, pathology laboratories could see how closely it was related to other known pathogens. They were able to identify it as a Betacoronavirus (Beta-CoVs), the family that also includes the viruses that cause SARS and Middle East Respiratory Syndrome (MERS).
This is a fast-moving story and medical laboratory leaders are advised to monitor the CDC website for continuing updates, as well as a website set up by WHO to provide technical guidance for labs.
