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Clinical Laboratories and Pathology Groups

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Clinical Laboratories and Pathology Groups

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Penn Medicine Researchers Develop Fast, Accurate, Inexpensive COVID-19 Diagnostic Test Based on Electrochemical Technology

The rapid diagnostic test costs less than $5 per unit and can be adapted for other diseases, the developers say, which opens a slew of possibilities for clinical laboratories

Just as the SARS-CoV-2 coronavirus spurred deployment of new vaccine technology based on messenger RNA (mRNA), the COVID-19 pandemic also could prove to be a watershed for in vitro diagnostics (IVD) innovation in ways that benefit clinical laboratories.

In one notable example, researchers at the Perelman School of Medicine University of Pennsylvania (Penn Medicine) in Philadelphia have developed a biosensor that uses electrochemical impedance spectroscopy (EIS) to detect the presence of the COVID-19 coronavirus in biological samples.

A Penn Medicine news release noted that “The RAPID technology … transforms the binding event between the SARS-CoV-2 viral spike protein and its receptor in the human body, the protein ACE2 (which provides the entry point for the coronavirus to hook into and infect human cells), into an electrical signal that clinicians and technicians can detect. That signal allows the test to discriminate between infected and healthy human samples. The signal can be read through a desktop instrument or a smartphone.”

Though still in its early stages, the technique potentially offers dramatically lower costs and faster results than traditional RT-PCR (reverse transcription polymerase chain reaction) molecular tests. Moreover, the RAPID technology might be useful for identifying other types of biomarkers and could be the basis for diagnostic tests that help reduce the cost-per-test in medical laboratory testing while providing comparable sensitivity and specificity to existing methodologies.

Clinical trials began on January 5, 2021, and the Penn Medicine researchers say the IVD test technology can be applied to other infectious diseases, which, if proven accurate, would be a boon to clinical laboratory testing.

The Penn Medicine researchers published their study on May 9 in the journal Matter, titled, “Low-Cost Biosensor for Rapid Detection of SARS-CoV-2 at the Point of Care.”

Diagnostic Test Results in Four Minutes for Less than $5/Test

According to the news release, the RAPID 1.0 (Real-time Accurate Portable Impedimetric Detection prototype 1.0) biosensor test costs less than $5 and can deliver results in four minutes. The researchers reported overall accuracy of 87.1% on (139) nasal swab samples and 90% on (50) saliva samples.

The technology uses electrodes that can be mass-produced at low cost on commercially-available screen printers, the researchers said. Results can be read on electronic devices connected to a PC or smartphone.

RAPID 1.0 COVID-19 diagnostic test

RAPID 1.0 (above) is a low-cost COVID-19 diagnostic test developed at the César de la Fuente clinical laboratory at the Perelman School of Medicine University of Pennsylvania in Philadelphia. At less than $5/test, plus the ability to be adapted to other diseases, clinical laboratories performing disease screenings in rural or remote locations may have a new tool in the fight against infections.  (Photo copyright: University of Pennsylvania.)

Does Penn Medicine’s RAPID 1.0 Test Replace Traditional RT-PCR Testing?

In their published study, the Penn Medicine researchers cited the need for “fast, reliable, inexpensive, and scalable point-of-care diagnostics.”

RT-PCR tests, they said, “are limited by their requirement of a large laboratory space, high reagent costs, multistep sample preparation, and the potential for cross-contamination. Moreover, results usually take hours to days to become available.”

Researchers who have studied the SARS-CoV-2 coronavirus know that it uses a spike-like protein to bind to angiotensin-converting enzyme 2 (ACE2) receptors on the surfaces of human cells.

As described in Penn Medicine’s published study, the biosensor contains ACE2 and other biochemical agents anchored to an electrode. When the SARS-CoV-2 coronavirus attaches to the ACE2, the biosensor transforms the chemical reaction into an electrical signal that can be measured on a device known as a potentiostat.

The researchers tested their RAPID 1.0 technology with two commercially available potentiostat models:

The researchers initially developed the electrode as a printed circuit board, which is relatively expensive. To reduce costs, they constructed a version that uses filter paper as the main component. The researchers noted that one screen printer in a lab can produce 35,000 electrodes per day, including time needed to incorporate the chemical elements. “However, it must be noted that these steps can be fully automated into a production line for industrial purposes, drastically reducing time requirements,” they wrote.

The test can be performed at room temperature, they added, and total cost per unit is $4.67. Much of that—$4.50—is for functionalizing the ACE2 recognition agent. The cost for the bare electrode is just seven cents.

“The overall cost of RAPID may be further reduced through recombinant production of ACE2 and ACE2 variants,” the researchers said, adding that the RAPID 1.0 test can detect the SARS-CoV-2 coronavirus at low concentrations correlating to the earliest stages of the COVID-19 disease.

Cesar de la Fuente, PhD

The Penn Medicine research team was led by César de la Fuente, PhD (above), an Assistant Professor in Psychiatry, Microbiology, Chemical and Biomolecular Engineering and Bioengineering at the Perelman School of Medicine. “Prior to the pandemic, our lab was working on diagnostics for bacterial infections,” he said in the Penn Medicine news release. “But then, COVID-19 hit. We felt a responsibility to use our expertise to help—and the diagnostic space was ripe for improvements.” (Photo copyright: University of Pennsylvania.)

Testing Penn Medicine’s RAPID 1.0 Test

The researchers evaluated the technology in blinded tests with clinical samples from the Hospital of the University of Pennsylvania. The evaluation included 139 nasal swab samples, of which 109 were determined to be COVID-19 positive by RT-PCR tests and clinical assessments. Among these, the RAPID test successfully detected the SARS-CoV-2 coronavirus in 91 samples, for a sensitivity rate of 83.5%. One sample was from a patient diagnosed with the highly contagious SARS-CoV-2 Alpha variant B.1.1.7, which the test correctly identified as positive.

Among the 30 samples determined to be COVID negative, the RAPID test scored a specificity rate of 100%, meaning no false positives. Overall accuracy, including sensitivity and specificity, was 87.1%.

The researchers also analyzed 50 saliva samples: 13 COVID-positive and 37 COVID-negative. The test correctly identified all 13 positive samples but produced five false-positives among the 37 negative samples, for a specificity rate of 86.5%. The researchers speculated that this could be due to interactions between ACE2 and other biomolecules in the saliva but suggested that performance “will improve when using fresh saliva samples at the point-of-care.”

Are There Other Applications for the RAPID Test?

The Penn Medicine news release said the RAPID technology can be adapted to detect other viruses, including those that cause Influenza and sexually-transmitted diseases.

Robert Michel, Editor-in-Chief of Dark Daily and its sister publication The Dark Report, said the test points to one silver lining in the COVID-19 pandemic. “Researchers around the world intensified their work to find ways to identify the SARS-CoV-2 virus that are faster, cheaper, and more accurate than the diagnostic technologies that existed at the time of the outbreak. In this regard, the COVID-19 pandemic may have accelerated the development and refinement of useful diagnostic technologies that will disrupt long-established methods of testing.”

Marcelo Der Torossian Torres, PhD, postdoctoral researcher at Penn Medicine and lead author of the study, said in the news release, “Quick and reliable tests like RAPID allow for high-frequency testing, which can help identify asymptomatic individuals who, once they learn they are infected, will stay home and decrease spread. 

“We envision this type of test being able to be used at high-populated locations such as schools, airports, stadiums, companies—or even in one’s own home,” he added.

Clinical laboratory managers may want to stay current on the development and possible commercialization of the RAPID 1.0 (Real-time Accurate Portable Impedimetric Detection prototype 1.0) biosensor test by the research team at Penn Medicine.

—Stephen Beale

Related Information

Low-Cost Biosensor for Rapid Detection of SARS-CoV-2 at the Point of Care

Rapid COVID-19 Diagnostic Test Delivers Results within Four Minutes with 90% Accuracy

UPenn Medical School Develops Low Cost COVID-19 Test Called RAPID

UPenn Working on Rapid COVID Test That Delivers Results Within Minutes

Rapid COVID-19 Test Developed at Penn Could Give On-the-Spot Results Quickly

One Step Closer to An At-Home, Rapid COVID-19 Test

February COVID-19 Superspreader Event in Boston Confirmed by Use of Genetic Sequencing as Next-Gen Sequencing Is Put to Novel Uses, including in Clinical Laboratories

Gene sequencing is enabling disease tracking in new ways that include retesting laboratory specimens from before the SARS-CoV-2 outbreak to determine when it arrived in the US

On February 26 of this year, nearly 200 executives and employees of neuroscience-biotechnology company Biogen gathered at the Boston Marriott Long Wharf hotel for their annual leadership conference. Unbeknownst to the attendees, by the end of the following day, dozens of them had been exposed to and become infected by SARS-CoV-2, the coronavirus that causes the COVID-19 illness.

Researchers now have hard evidence that attendees at this meeting returned to their communities and spread the infection. The findings of this study will be relevant to pathologists and clinical laboratory managers who are cooperating with health authorities in their communities to identify infected individuals and track the spread of the novel coronavirus.

This “superspreader” event has been closely investigated and has led to intriguing conclusions concerning the use of genetic sequencing to revealed vital information about the COVID-19 pandemic. Recent improvements in gene sequencing technology is giving scientists new ways to trace the spread of COVID-19 and other diseases, as well as a method for monitoring mutations and speeding research into various treatments and vaccines. 

Genetic Sequencing Traces an Outbreak

“With genetic data, a record of our poor decisions is being captured in a whole new way,” Bronwyn MacInnis, PhD, Director of Pathogen Genomic Surveillance at the Broad Institute of MIT and Harvard, told The Washington Post (WaPo) during its analysis of the COVID-19 superspreading event. MacInnis is one of many Broad Institute, Harvard, MIT, and state of Massachusetts scientists who co-authored a study that detailed the coronavirus’ spread across Boston, including from the Biogen conference.

Titled, “Phylogenetic Analysis of SARS-CoV-2 in the Boston Area Highlights the Role of Recurrent Importation and Superspreading Events,” the paper explains how the researchers “sequenced and analyzed 772 complete SARS-CoV-2 genomes from the region” in order to investigate how the virus was introduced and spread through the area. They traced a specific mutation in the virus—“a simple switch of two letters in the virus’ 30,000-character genetic code,” WaPo reported.

What they discovered is both surprising and enlightening. According to WaPo’s report, at least 35 new cases of the virus were linked directly to the Biogen conference, and the same strain was discovered in outbreaks in two homeless shelters in Boston, where 122 people were infected. The variant tracked by the Boston researchers was found in roughly 30% of the cases that have been sequenced in the state, as well as in Alaska, Senegal, and Luxembourg.

“The data reveal over 80 introductions into the Boston area, predominantly from elsewhere in the United States and Europe. We studied two superspreading events covered by the data, events that led to very different outcomes because of the timing and populations involved. One produced rapid spread in a vulnerable population but little onward transmission, while the other was a major contributor to sustained community transmission,” the researchers noted in their study abstract.

“The same two events differed significantly in the number of new mutations seen, raising the possibility that SARS-CoV-2 superspreading might encompass disparate transmission dynamics. Our results highlight the failure of measures to prevent importation into [Massachusetts] early in the outbreak, underscore the role of superspreading in amplifying an outbreak in a major urban area, and lay a foundation for contact tracing informed by genetic data,” they concluded.

Anthony Fauci, MD
Some experts think humankind may be entering a period of increased pandemics. In their report published in Cell, titled, “Emerging Pandemic Diseases: How We Got to COVID-19,” Anthony Fauci, MD (above) Director of the National Institute of Allergy and Infectious Diseases (NIAID), and David Morens, MD, a senior associate professor at Johns Hopkins School of Public Health and Senior Advisor to Fauci, wrote, “One can conclude from this recent experience that we have entered a pandemic era. The causes of this new and dangerous situation are multifaceted, complex, and deserving of serious examination.” (Photo copyright: NIAID.)

Genetic Sequencing and Mutation Tracking

The use of genetic sequencing to trace the virus could inform measures to control the spread in new ways, but currently, only about 0.33% of cases in the United States are being sequenced, MacInnis told WaPo, and that not sequencing samples is “throwing away the crown jewels of what you really want to know.”

Another role that genetic sequencing is playing in this pandemic is in tracking viral mutations. One of the ways that pandemics worsen is when viruses mutate to become deadlier or more easily spread. Scientists are using genetic sequencing to monitor SARS-CoV-2 for such mutations.

A group of scientists at Texas A&M University led by Yue Xing, PhD, published a paper titled, “MicroGMT: A Mutation Tracker for SARS-CoV-2 and Other Microbial Genome Sequences,” which explains that “Although most mutations are expected to be selectively neural, it is important to monitor if SARS-CoV-2 will eventually evolve to be a stronger or weaker infectious agent as time goes on. Therefore, it is vital to track mutations from newly sequenced SARS-CoV-2 genome.”

Another group of researchers have identified such a mutation. “A SARS-CoV-2 variant carrying the Spike protein amino acid change D614G has become the most prevalent form in the global pandemic. Dynamic tracking of variant frequencies revealed a recurrent pattern of G614 increase at multiple geographic levels: national, regional, and municipal,” Bette Korber, PhD and her colleagues wrote in “Tracking Changes in SARS-CoV-2 Spike: Evidence That D614G Increases Infectivity of the COVID-19 Virus,” published in Cell. Korber is a Laboratory Fellow at Los Alamos National Laboratory and visiting faculty at Santa Fe Institute.

Korber’s findings are important because the mutation the scientists identified appears to have a fitness advantage. “Our data show that, over the course of one month, the variant carrying the D614G Spike mutation became the globally dominant form of SARS-CoV-2,” they wrote. Additionally, the study noted, people infected with the mutated variant appear to have a higher viral load in their upper respiratory tracts.

Genetic Sequencing, the Race for Treatments, Vaccines, and Managing Future Pandemics

A vaccine is the best hope for stopping a pandemic, but short of a vaccine, an effective clinical laboratory treatment is the next best thing. And as Dark Daily reported in “Advances in Gene Sequencing Technology Enable Scientists to Respond to the Novel Coronavirus Outbreak in Record Time with Medical Lab Tests, Therapies,” genetic sequencing is quickly becoming a critical tool to develop both.

If, as Fauci and Morens predict, future pandemics are likely, improvements in gene sequencing and analysis will become even more important for tracing, monitoring, and suppressing outbreaks. Clinical laboratory managers will want to watch this closely, as medical labs that process genetic sequencing will, no doubt, be part of that operation.

—Dava Stewart

Related Information:

Genetic Data Show How a Single Superspreading Event Sent Coronavirus Across Massachusetts and the Nation

How the Biogen Leadership Conference in Boston Spread the Coronavirus

How a Premier U.S. Drug Company Became a Virus ‘Super Spreader’

This Cambridge Drug Company Inadvertently Spread the Coronavirus. Now, It’s Creating A ‘Biobank’ To Hopefully Treat the Disease

Phylogenetic Analysis of SARS-CoV-2 in the Boston Area Highlights the Role of Recurrent Importation and Superspreading Events

MicroGMT: A Mutation Tracker for SARS-CoV-2 and Other Microbial Genome Sequences

Tracking Changes in SARS-CoV-2 Spike: Evidence That D614G Increases Infectivity of the COVID-19 Virus

The D614G Mutation in the SARS-CoV-2 Spike Protein Reduces S1 Shedding and Increases Infectivity

Emerging Pandemic Diseases: How We Got to COVID-19 Advances in Gene Sequencing Technology Enable Scientists to Respond to the Novel Coronavirus Outbreak in Record Time with Medical Lab Tests, Therapies

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