COVID-19 Tests | Wish List

Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

New COVID-19 test uses a smartphone microscope to quickly analyze saliva samples

1/29/21 ... mples.aspx

Researchers at the University of Arizona are developing a COVID-19 testing method that uses a smartphone microscope to analyze saliva samples and deliver results in about 10 minutes.

The UArizona research team, led by biomedical engineering professor Jeong-Yeol Yoon, aims to combine the speed of existing nasal swab antigen tests with the high accuracy of nasal swab PCR, or polymerase chain reaction, tests. The researchers are adapting an inexpensive method that they originally created to detect norovirus - the microbe famous for spreading on cruise ships - using a smartphone microscope.

They plan to use the method in conjunction with a saline swish-gargle test developed by Michael Worobey, head of the UArizona Department of Ecology and Evolutionary Biology and associate director of the University of Arizona BIO5 Institute.

The team's latest research using water samples - done in collaboration with Kelly A. Reynolds, chair of the Department of Community, Environment and Policy in the UArizona Mel and Enid Zuckerman College of Public Health - is published today in Nature Protocols.

" We've outlined it so that other scientists can basically repeat what we did and create a norovirus-detecting device. Our goal is that if you want to adapt it for something else, like we've adapted it for COVID-19, that you have all the ingredients you need to basically make your own device."

- Lane Breshears, Biomedical Engineering Doctoral Student

Yoon - a BIO5 Institute member who is also a professor of biosystems engineering, animal and comparative biomedical sciences, and chemistry and biochemistry - is working with a large group of undergraduate and graduate students to develop the smartphone-based COVID-19 detection method.

"I have a couple of friends who had COVID-19 that were super frustrated, because their PCR results were taking six or seven days or they were getting false negatives from rapid antigen tests. But when they got the final PCR tests, they found out they had been sick, like they'd suspected," said Katie Sosnowski, a biomedical engineering doctoral student who works in Yoon's lab. "It's really cool to be working on a detection platform that can get fast results that are also accurate."

Cheaper, simpler detection

Traditional methods for detection of norovirus or other pathogens are often expensive, involve a large suite of laboratory equipment or require scientific expertise. The smartphone-based norovirus test developed at UArizona consists of a smartphone, a simple microscope and a piece of microfluidic paper - a wax-coated paper that guides the liquid sample to flow through specific channels. It is smaller and cheaper than other tests, with the components costing about $45.

The basis of the technology, described in a 2019 paper published in the journal ACS Omega, is relatively simple. Users introduce antibodies with fluorescent beads to a potentially contaminated water sample. If enough particles of the pathogen are present in the sample, several antibodies attach to each pathogen particle. Under a microscope, the pathogen particles show up as little clumps of fluorescent beads, which the user can then count. The process - adding beads to the sample, soaking a piece of paper in the sample, then taking a smartphone photograph of it under a microscope and counting the beads - takes about 10 to 15 minutes. It's so simple that Yoon says a nonscientist could learn how to do it by watching a brief video.

The version of the technology described in the Nature Protocols paper makes further improvements, such as creating a 3D-printed housing for the microscope attachment and microfluidic paper chip. The paper also introduces a method called adaptive thresholding. Previously, researchers set a fixed value for what quantity of pathogen constituted a danger, which limited precision levels. The new version uses artificial intelligence to set the danger threshold and account for environmental differences, such as the type of smartphone and the quality of the paper.

On-campus impact

The researchers plan to partner with testing facilities at the University of Arizona to fine-tune their method as they adapt it for COVID-19 detection. Pending approval of the university's institutional review board, students who are already being tested on campus through other methods will have the option to provide written consent for their sample to be run through the smartphone-based testing device as well. Ultimately, the researchers envision distributing the device to campus hubs so that the average person - such as a resident assistant in a dorm - could test saliva samples from groups of people.

"Adapting a method designed to detect the norovirus - another highly contagious pathogen - is an outstanding example of our researchers pivoting in the face of the pandemic," said University of Arizona President Robert C. Robbins. "This promising technology could allow us to provide fast, accurate, affordable tests to the campus community frequently and easily. We hope to make it a regular part of our 'Test, Trace, Treat' strategy, and that it will have a broader impact in mitigating the spread of the disease."

Yoon and his team are also working on another idea, based on a 2018 paper they published in Chemistry--A European Journal, which is even simpler but leaves slightly more room for error. It involves the same technology, but instead of a smartphone microscope and specially designed enclosure, users would only need to download a smartphone app and use a microfluidic chip stamped with a QR code.

"Unlike the fluorescent microscope technique, where you get the chip into just the right position, you just take a snapshot of the chip," said biomedical engineering master's student Pat Akarapipad. "No matter the angle or distance the photo is taken from, the smartphone app can use AI and the QR code to account for variances and run calculations accordingly."

The method requires no training, so, if perfected, it could potentially allow students to pick up microfluidic chips from a campus location and test their own samples. The team is also working with other members of the university's COVID-19 testing group, including Deepta Bhattacharya, an associate professor in the Department of Immunobiology.


University of Arizona College of Engineering

Journal reference:

Chung, S., et al. (2021) Norovirus detection in water samples at the level of single virus copies per microliter using a smartphone-based fluorescence microscope. Nature Protocols.
Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

Startup develops yeast-based test to detect the presence of SARS-CoV-2 in saliva

1/29/21 ... aliva.aspx

Incubated at the University of Campinas (UNICAMP) in the state of São Paulo, Brazil, and supported by São Paulo Research Foundation- FAPESP's Innovative Research in Small Business Program (PIPE), BIOinFOOD is a startup that is developing a rapid COVID-19 diagnostic test based on a patent application filed by students at UNICAMP's Genomics and Bioenergy Laboratory.

The test is based on a biosensor consisting of a genetically modified brewer's yeast (Saccharomyces cerevisiae), which changes color if human ACE2 receptor expressed by the yeast's membrane binds to the spike glycoprotein present on the external surface of the virus.

" The yeast is normally beige. When this interaction takes place, the presence of the virus is signaled by a fluorescent green that can easily be detected by the equipment typically found in clinical analysis labs."

- Gleidson Silva Teixeira, one of BIOinFOOD's partners

Teixeira studied under Professor Gonçalo Amarante Guimarães Pereira, who leads one of the laboratories at UNICAMP's Institute of Biology, where the idea came up. According to the researchers' expectations, the new test will be both fast and cheaper than RT-PCR because of the low cost of yeast, the main input.

Another important difference is that it will probably use saliva. Being non-invasive is an advantage for diagnostic tests. Many people experience intense discomfort when undergoing collection of their material by nasal swab.

The sensitivity of the test is expected to be high, meaning it will be able to detect the virus only a few days after infection. "We plan eventually to have the yeast emit red light, which will be easier to identify," Teixeira says. "In this case, anyone will be perfectly capable of using the test, even at home."

Once the working hypothesis formulated in UNICAMP's laboratories has been fully validated, the startup's scientists expect the test to be brought to market and freely available for purchase during first-half 2021.

"The project is also supported by FINEP [the Brazilian government's innovation agency] and must be developed rapidly because we can't miss an opportunity to help combat the pandemic," Teixeira says.

The idea of developing a product designed to combat COVID-19 arose from a call issued by FAPESP when the pandemic arrived in Brazil (in March 2020), inviting researchers in the state of São Paulo to submit proposals for creative solutions in this direction. "The secret, in this case, is genetic modification of the yeast," Teixeira says. "We're confident the hypothesis will work and the biosensor we're constructing will emit a totally reliable signal."

The raw materials for the product are simple and distribution of the diagnostic test should be logistically straightforward.

Bread and beer

The innovation involved in the COVID-19 diagnostic test came out of a technology mastered previously by BIOinFOOD, according to one of its owners. The startup offers a biotech platform based on S. cerevisiae, a versatile microorganism widely used in industry as a biofactory. Organic acids, amino acids, enzymes, and therapeutic proteins are some of the outputs of the platform.

"In the specific case of the technology used to develop the COVID-19 test, we want to see the platform being adapted to other types of disease in future," Teixeira says.

The firm also develops custom yeasts for use by bakeries and breweries to suit consumer tastes. "We have several yeast-based solutions. Yeasts are well-known microorganisms. They can also be used in animal feed," Teixeira says.


São Paulo Research Foundation (FAPESP)
Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

Wearable devices can identify COVID-19 cases earlier than traditional diagnostic methods

2/8/21 ... thods.aspx

Wearable devices can identify COVID-19 cases earlier than traditional diagnostic methods and can help track and improve management of the disease, Mount Sinai researchers report in one of the first studies on the topic. The findings were published in the Journal of Medical Internet Research on January 29.

The Warrior Watch Study found that subtle changes in a participant's heart rate variability (HRV) measured by an Apple Watch were able to signal the onset of COVID-19 up to seven days before the individual was diagnosed with the infection via nasal swab, and also to identify those who have symptoms.

" This study highlights the future of digital health. It shows that we can use these technologies to better address evolving health needs, which will hopefully help us improve the management of disease. Our goal is to operationalize these platforms to improve the health of our patients and this study is a significant step in that direction. Developing a way to identify people who might be sick even before they know they are infected would be a breakthrough in the management of COVID-19."

- Robert P. Hirten, MD, Study Corresponding Author and Assistant Professor of Medicine (Gastroenterology), Icahn School of Medicine, Mount Sinai

Hirten is also a member of the Hasso Plattner Institute for Digital Health at Mount Sinai and the Mount Sinai Clinical Intelligence Center (MSCIC).

The researchers enrolled several hundred health care workers throughout the Mount Sinai Health System in an ongoing digital study between April and September 2020. The participants wore Apple Watches and answered daily questions through a customized app. Changes in their HRV--a measure of nervous system function detected by the wearable device--were used to identify and predict whether the workers were infected with COVID-19 or had symptoms.

Other daily symptoms that were collected included fever or chills, tiredness or weakness, body aches, dry cough, sneezing, runny nose, diarrhea, sore throat, headache, shortness of breath, loss of smell or taste, and itchy eyes.

Additionally, the researchers found that 7 to 14 days after diagnosis with COVID-19, the HRV pattern began to normalize and was no longer statistically different from the patterns of those who were not infected.

"This technology allows us not only to track and predict health outcomes, but also to intervene in a timely and remote manner, which is essential during a pandemic that requires people to stay apart," says the study's co-author Zahi Fayad, PhD, Director of the BioMedical Engineering and Imaging Institute, Co-Founder of the MSCIC, and the Lucy G. Moses Professor of Medical Imaging and Bioengineering at the Icahn School of Medicine at Mount Sinai.

The Warrior Watch Study draws on the collaborative effort of the Hasso Plattner Institute for Digital Health and the MSCIC, which represents a diverse group of data scientists, engineers, clinical physicians, and researchers across the Mount Sinai Health System who joined together in the spring of 2020 to combat COVID-19. The study will next take a closer look at biometrics including HRV, sleep disruption, and physical activity to better understand which health care workers are at risk of the psychological effects of the pandemic.


The Mount Sinai Hospital / Mount Sinai School of Medicine
Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

FDA grants emergency use authorization for QuickVue At-Home COVID-19 Test

3/1/21 ... -Test.aspx

Today, the U.S. Food and Drug Administration issued an emergency use authorization (EUA) for the Quidel QuickVue At-Home COVID-19 Test, another antigen test where certain individuals can rapidly collect and test their sample at home, without needing to send a sample to a laboratory for analysis.

The QuickVue At-Home COVID-19 Test is authorized for prescription home use with self-collected anterior nasal (nares) swabs from individuals ages 14 and older or individuals ages 8 and older with swabs collected by an adult. The test is authorized for individuals suspected of COVID-19 by their healthcare provider within the first six days of symptom onset.

" The FDA continues to prioritize the availability of more at-home testing options in response to the pandemic. The QuickVue At-Home COVID-19 Test is another example of the FDA working with test developers to bring important diagnostics to the public."

- Jeff Shuren, M.D., J.D., Director, FDA's Center for Devices and Radiological Health

In addition to this new prescription home test, Quidel also was issued an EUA in December 2020 for their QuickVue SARS Antigen Test which is authorized for use in laboratories certified under the Clinical Laboratory Improvement Amendments (CLIA) to perform high, moderate or waived complexity tests, as well as for point-of-care testing by facilities operating under a CLIA Certificate of Waiver.


U.S. Food and Drug Administration
Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

Sniffer dogs could be used to detect SARS-CoV-2 infections, say researchers

3/8/21 ... chers.aspx

Researchers in Germany suggest that sniffer dogs should be considered as an additional screening tool for detecting infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) – the agent that causes coronavirus disease 2019 (COVID-19).

The team found that dogs could discriminate between saliva samples from people with and without SARS-CoV-2 infection with a sensitivity of 84% and a specificity of 95%.

The dogs were also able to detect the scent of SARS-CoV-2 infection in sweat and urine samples, with sensitivity and specificity as high as 95% and 98%, respectively, for urine samples.

Holger Andreas Volk from the University of Veterinary Medicine Hannover in Bünteweg and colleagues say the results suggest that sniffer dogs could be added to the current gold standard method for detecting SARS-CoV-2.

The team advises that dogs should be considered for rapid testing in various situations where many people from different origins come together, such as airports or concerts.

A pre-print version of the research paper is available on the bioRxiv* server, while the article undergoes peer review.

The current approaches to containing COVID-19

The primary approach to containing the COVID-19 pandemic is ongoing testing, tracing and quarantining while enough vaccines are administered to protect a sufficient proportion of the population.

The SARS-CoV-2 virus is currently detected using the “gold standard” reverse transcription-polymerase chain reaction (RT-PCR) and slightly less sensitive but more rapid tests of nasal or pharyngeal swabs and saliva.

However, “it remains unclear whether sweat or urine are also sources of viral transmission,” says Volk and colleagues.

How might dogs detect infection?

Renowned for their extraordinary olfactory sense, dogs are often deployed for real-time detection of drugs and explosives, for example.

Infectious diseases can produce specific odors through the generation of volatile organic compounds (VOCs) – products of metabolism emitted in the breath, saliva, sweat and urine.

Multiple studies have shown that dogs can detect infectious and non-infectious diseases such as cancer, malaria, bacterial infection, hypoglycemia in diabetics, and viral infection in cell cultures.

Several research groups are currently training and deploying dogs for the detection of SARS-CoV-2 infection.

In a pilot study, Volk and colleagues recently showed that dogs were able to detect inactivated saliva samples from COVID-19 patients with a sensitivity of 83% and a specificity of 96%.

However, it remains to be shown whether dogs can detect biofluid-specific VOCs or a more general change in the odor of COVID-19 patients.

What did the current study involve?

In the former pilot study, only beta-propiolactone (BPL)-inactivated samples from COVID-19 patients were used.

“The first step in the current study was, therefore, to assess whether dogs can transfer scent recognition to non-inactivated saliva samples, even when trained only with inactivated samples,” says Vol and colleagues.

Ten German armed force’s service dogs were trained for a period of 8 days to recognize the scent of SARS-CoV-2 infection using BPL-inactivated saliva samples. The researchers then tested whether the animals could transfer their smell recognition to non-inactivated saliva, urine and sweat samples from infected patients.

The animals recognized the scent of SARS-CoV-2 infection with a sensitivity and specificity of 95% and 98%, respectively, for urine samples, 91% and 94% for sweat samples, and 82% and 96% for saliva samples.

“After only eight days of training, dogs were not only able to immediately transfer their scent detection abilities from inactivated to non-inactivated saliva samples, but also to sweat and urine, with urine having the highest sensitivity of 95% and specificity of 98%,” writes the team.

The researchers say the findings show that global, non-tissue-specific SARS-CoV-2-associated VOCs are released across different bodily secretions

What does the team advise?

The current study suggests that dogs can be safely trained within little more than a week to become reliable SARS-CoV-2 detection dogs, says volk and colleagues.

“Sniffer dogs should be considered an addition to the gold standard RT-PCR, for rapid testing in situations where great numbers of people from different origins come together,” they write.

“Further work, especially under real-life conditions in settings where many individuals have to be screened is needed to fully evaluate the potential of the dog detection method,” concludes the team.

*Important Notice

bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:

Volk HA, et al. Scent dog identification of SARS-CoV-2 infections, similar across different body fluids. bioRxiv, 2021. doi:, ... 5.434038v1
Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

Backed by millions in public and private cash, rapid Covid tests are coming to stores near you

4/1/21 ... r-you.aspx

Scientists and lawmakers agree that over-the-counter Covid tests could allow desk workers to settle back into their cubicles and make it easier to reopen schools and travel.

But even as entrepreneurs race their products to market, armed with millions of dollars in venture capital and government investment, the demand for Covid testing has waned. Manufacturing and bureaucratic delays have also kept rapid tests from hitting store shelves in large numbers, though the industry was energized by the Food and Drug Administration's greenlighting of two more over-the-counter tests Wednesday.

Corporate giants and startups alike plan to offer a dizzying array of test options, most costing between $10 and $110. Their screening accuracy varies, as does the way consumers get results: collection kits mailed back to a lab, devices synced with artificial intelligence-enabled apps on a smartphone that spit out results within 15 minutes, and credit card-sized tests with strips of paper that must be dipped into a chemical substance.

"At-home tests are one of the key steps to getting back to normal life," said Andy Slavitt, a member of the White House Covid-19 Response Team, during a February briefing.

The Biden administration announced in March it will allocate $10 billion from the recently passed stimulus package for Covid testing to expedite school reopenings, and earlier said it would invoke the Defense Production Act to manufacture more at-home tests. Separately, the federal government has already sent millions of Abbott Laboratories' BinaxNOW rapid tests to states, and California, for instance, is giving 3 million of them to its most disadvantaged school districts for free.

Large employers, like Google, sports leagues and the federal government, have already shelled out millions to regularly test their workers. Amazon just received emergency use authorization from the FDA for its own Covid test and home collection kit, which it intends to use for its employee screening program.

Individuals who want to buy over-the-counter tests can bill their health insurance plans, which are required by the federal government in most cases to fully cover Covid tests that have been authorized by the FDA.

Everlywell, based in Austin, Texas, is an at-home diagnostic company that already sells its collection kit to consumers through its website and Walgreens, and will soon offer same-day delivery via DoorDash in a dozen cities. Dr. Marisa Cruz, Everlywell's executive vice president of regulatory and clinical affairs, said buyers can seek reimbursement from their insurance plans for the kit's $109 cost. The tests are also eligible for purchase with pretax dollars from health savings or flexible spending accounts, she said.

Even with vaccines, epidemiologists say, rapid tests are desperately needed because more testing, along with mask-wearing and physical distancing, will get people back in offices and classrooms and help catch cases that go undetected. A report by the Centers for Disease Control and Prevention found that, of people with active infections, 44% reported no symptoms.

But the market for over-the-counter tests is risky. Demand for testing has plunged dramatically since the height of the winter surge and may not rebound as more people are vaccinated.

"You clearly are at risk of missing the market," said Michael Greeley, co-founder and general partner at Flare Capital Partners, a venture capital firm focused on health care technology.

But Douglas Bryant, president and CEO of Quidel Corp., remains unfazed, even after the diagnostics manufacturer's testing demand dropped by about one-third in the past two months.

"The level of testing for people with symptoms and the 'worried well,' who see others getting tested and think they should, too, is subsiding," Bryant said. "But once we start to get more people vaccinated, the government will move from campaigning to get people vaccinated to saying, 'Please test yourself regularly so we can get back to work.'"

Quidel, headquartered in San Diego, recently unveiled its latest test, the QuickVue At-Home Covid-19 Test, which takes 10 minutes to detect the coronavirus by homing in on specific proteins, called antigens. The FDA authorized the test for over-the-counter use Wednesday, and Quidel plans to announce retail partners in the coming weeks.

The FDA said in mid-March it would speed the pipeline for "screening testing," including at-home Covid tests that don't require consumers to have symptoms or a prescription.

In February, the Biden administration cut a $232 million deal with Ellume, whose rapid antigen test was authorized by the FDA in December. Paired with an app, the test takes 15 minutes to analyze after a nose swab.

The Australian company currently ships hundreds of thousands of test kits a week to the U.S. from its factory in Brisbane to large companies and the Department of Defense. It plans to be on the shelves of multiple pharmacies by the second half of the year and in one major retailer in April, said Dr. Sean Parsons, the company's founder and CEO.

"We are going as fast as we can possibly go," he said.

The main holdup for Ellume has been getting enough swabs for its production line. The company is building a factory in the U.S. to reduce international shipping costs and increase production.

Abbott, which dominates the rapid-test market, said in January it expects to sell 120 million BinaxNOW antigen tests to consumers in the first half of the year. People who take the test now must do so under observation by telemedicine platform eMed. But Abbott received authorization from the FDA this week for an over-the-counter version that won't require remote observation or a prescription. The test will be available in U.S. stores in the coming weeks, the company said.

Throughout the pandemic, the government has depended heavily on medical device behemoth Abbott's testing options. The company's rapid-diagnostics arm alone has snared $673 million in federal contracts to combat the coronavirus, according to a ProPublica database. This includes bulk purchases made by the Defense Department, the national prison system, Immigration and Customs Enforcement, the State Department and former President Donald Trump's office.

But antigen tests sometimes report false negatives, particularly among people without symptoms, noted Dr. Jac Dinnes, who co-authored a review of 64 Covid test studies. By comparison, polymerase chain reaction (PCR) tests — generally employed by commercial labs — are more sensitive. PCR tests search for the virus's genetic material over multiple testing cycles, which magnifies what's in the swab sample, requiring a much smaller viral load for detection.

Antigen tests are the basis for most at-home screening, but the FDA has also authorized two at-home options — made by Lucira Health and Cue Health — that use molecular processes similar to a PCR test.

Still, many experts support the widespread distribution of cheap, rapid tests, even if they aren't as sensitive as lab-run alternatives, and see a demand. In Germany, the supermarket chain Aldi began selling rapid tests in early March, roughly $30 for a five-pack, and sold out within hours. One recent study found that if a pack of tests was mailed to every household in the U.S. — even assuming that up to 75% would go into the garbage — they would save thousands of lives and avert millions of infections.

"Don't let perfect be the enemy of good," said study co-author and Yale University professor A. David Paltiel. "This doesn't have to work perfectly to make a huge difference."

Some companies are working on rapid-testing options that more precisely read samples, such as Gauss.

The Menlo Park, California, health tech company, which before the pandemic created an artificial intelligence-based app to measure surgical blood loss in real time, aims to harness its expertise to improve on the basic antigen test. It took about a week for CEO Siddarth Satish to raise $30 million of venture capital last October.

Its Covid-testing app uses facial recognition software to confirm that test-takers correctly swab their noses. The app provides step-by-step instructions and timers. After 15 minutes, an algorithm based on thousands of sample tests interprets the result — which displays as a colored line, as with a pregnancy test — using the phone's camera.

Gauss and Cellex, which manufactures the Gauss tests, await FDA authorization. In the meantime, they have produced more than 1.5 million kits and struck deals with supermarket chain Kroger and e-pharmacy site Truepill to sell them for about $30.

"A huge part of the accuracy issue with rapid tests is that you have to visually interpret them," Satish said. "Sometimes you get really faint lines, just like with a pregnancy strip, and there's some guesswork."

Lucira Health, based in Emeryville, California, uses something called loop-mediated isothermal amplification technology, which is similar to PCR tests in precision. In February, the company went public, raising $153 million largely to fund the manufacturing of its all-in-one testing kit, currently prescribed by doctors across the country. The kit comes with a nose swab and a vial of chemicals analyzed by a hand-held device — taking up to 30 minutes for results.

Kelly Lewis Brezoczky, Lucira's executive vice president, envisions the test kit on the shelf in local pharmacies, perched next to the NyQuil. "I always like to tell people that it is as easy to use as toothpaste," she said.
Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

SCIENCE FAIL: Review finds rapid coronavirus test kits miss 42% of asymptomatic cases and are prone to false-positive results

3/29/21 ... cases.html

A major review found that rapid coronavirus tests can miss as many as two-fifths of infected people without symptoms. Lateral flow test kits are a quick testing method to find if someone is positive for the Wuhan coronavirus, giving results in as fast as 30 minutes. However, researchers who examined 64 studies of the test kits found that they failed to spot 42 percent of asymptomatic cases.

Lateral flow tests do not require trained medical personnel to administer them. Teachers and pupils use lateral flow test kits on an everyday basis to track COVID-19 infections in schools. Aside from schools, these kits are also used at care homes, hospitals and business establishments.

The researchers behind the review examined earlier studies mostly coming from the U.S. and Europe that scrutinized the accuracy of rapid antigen tests. Their paper published March 24 in the reputable Cochrane Library found that on average, lateral flow test kits only identified 58 percent of asymptomatic COVID-19 patients. On the other hand, the review found that these rapid test kits accurately identified 78 percent of patients exhibiting COVID-19 symptoms. The World Health Organization (WHO) set an 80 percent minimum standard for correctly detecting those with COVID-19 using tests.

The researchers wrote: “In a population of 1,000 people with symptoms, where there are 50 people with [COVID-19] – we would expect that about 40 people would be correctly identified as having [the disease] by rapid test, and between six and 12 cases would be missed.”

It was also found in the review that lateral flow test kits had a high tendency to give false-positive results. The report explained that in a population of 10,000 asymptomatic people, between 125 and 213 positive results would turn out – with around 90 to 189 of those positive results being false-positive ones. (Related: Inaccurate test results, patient histories fuel more coronavirus speculation.)

The inaccurate lateral flow test kits could contribute to the spread of the coronavirus instead of stopping it

The review’s findings caused concern among scientists, given that at least 50 percent of asymptomatic patients transmit COVID-19. While children are less likely to suffer from COVID-19, they can still spread the pathogen responsible for it. Thus, the scientists also voiced out concerns about the use of the test kits in schools.

University of Birmingham biostatistician and report author Jon Deeks said government ministers may have rushed the use of lateral flow test kits in schools “without any supporting real-world evidence.” KU Leuven associate professor of primary care and fellow review author Dr. Ann Van den Bruel also warned that the risk of false positives in these tests “is very high.” She commented: “You may end up having the opposite effect of what you want to achieve and you may have to close more workplaces [and] more [school] classes.”

Meanwhile, University of Birmingham epidemiologist and another review author Dr. Jac Dinnes remarked that the lateral flow test kits “do not appear to perform as well” in asymptomatic people infected with the coronavirus. “Our review showed that some antigen tests may be useful in healthcare settings where [COVID-19] is suspected in people with symptoms,” she said.

Dinnes continued: “All antigen tests will miss some people with infection, so it is important to inform people who receive a negative test result that they may still be infected.” She also suggested that those with a positive antigen test result undergo a confirmatory RT-PCR test, which is more accurate in detecting the coronavirus. This may help avoid unnecessary quarantine particularly in areas with low COVID-19 case counts, Dinnes explained. (Related: Abbott Labs’ five-minute coronavirus test misses HALF of positive cases.)

The accuracy of lateral flow test kits and other rapid antigen testing systems for COVID-19 has been put into question. Two incidents have shown that these inaccurate testing methods for the coronavirus miss detecting the pathogen in some infected people – but detect non-human samples as COVID-19 positive.

Back in May 2020, the late Tanzanian President John Magufuli sent samples taken from a goat and a papaya to a laboratory for coronavirus testing. The samples were given human names and ages, and lab technicians were not told of the samples’ origins. The goat and papaya samples tested positive for COVID-19, which led Magufuli to surmise that Tanzania was utilizing faulty test kits. He added that the faulty kits meant some people tested positive for the coronavirus without actually being infected.

In December 2020, National Council of Austria member Michael Schnedlitz slammed the inaccurate antigen rapid test being used in the country. The lawmaker brought a glass of Coca-Cola to the podium before beginning his speech. He then sprinkled a few drops of the soft drink on a rapid test kit – which then reflected a positive test result. Schnedlitz then proceeded with his speech by calling the test kits “worthless” and the Austrian government’s purchase of those as akin to “throwing tens of millions of tax money out of the window.”
Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

COVID-19 test detects antibodies in hundreds of tiny blood samples

5/3/21 ... blood.html

Antibody testing can be a powerful tool for tracking the spread of SARS-CoV2 infections, the virus responsible for the COVID-19 pandemic. A group of scientists from EPFL, UNIGE and HUG have now developed a reliable and cheap antibody test that can analyze more than 1,000 samples at once and requires a small drop of blood, such as that from a finger prick.

After people get infected with the SARS-CoV-2 virus that causes COVID-19, they start to produce immune molecules called antibodies. COVID-19 antibody tests pick up on the presence of antibodies against SARS-CoV-2 in the blood. Because antibodies can take several days to weeks to develop, antibody tests can't detect active infections, but they can help to find out what proportion of communities have been infected with the virus in the past. This knowledge is useful for epidemiological investigations, and informing public-health policies. Antibody tests are also a powerful tool to evaluate COVID-19 vaccine efficacy in clinical trials, when scientists look at the rise in antibodies after volunteers get a jab.

However, antibody tests rely on rather expensive reagents and typically require larger quantities of blood taken with a venous blood draw, which can only be performed by trained healthcare personnel. What's more, some of the tests on the market are too inaccurate to deliver reliable results. Now, researchers from EPFL, UNIGE and HUG have developed a highly accurate test that can analyze hundreds of samples at the same time, using minute quantities of reagents and single drops of blood.

"The coolest thing about our approach is that you can do a lot of tests at once with minimal reagents, and you could even have people collect their own blood samples at home," says study first author Zoe Swank, a former Ph.D. student in the EPFL's Laboratory of Biological Network Characterization led by Sebastian Maerkl.

In early 2020, Swank and Maerkl teamed up with Benjamin Meyer, a virologist at UNIGE Faculty of Medicine and scientific collaborator at HUG Division of Laboratory Medicine, and with Isabella Eckerle, a professor at UNIGE Faculty of Medicine and Medical Coordinator of the UNIGE-HUG Centre for Emerging Viral Diseases, and set out to repurpose a diagnostics platform that had been previously developed in Maerkl's lab, so that it could be used to perform SARS-CoV-2 antibody tests.

The platform, which can analyze up to 1,024 samples at once, consists of a complex network of tiny tubes carved into a plastic chip that is about the size of a USB stick. To perform the assay, the researchers feed individual blood samples and test reagents through the channels of this 'microfluidic' chip. If antibodies against SARS-CoV-2 are present in a blood sample, a molecule generates a signal that can be detected as a fluorescent glow under a microscope.

When the team tested blood samples from 155 individuals infected with SARS-CoV-2, the assay detected antibodies against the virus in 98% of cases. The assay is also extremely specific: it never detected antibodies against the virus in samples from people who had not been infected with SARS-CoV-2.

Because the microfluidic device is very small, the amounts of blood and reagents used are a fraction of those required for standard COVID-19 antibody tests. And running hundreds of assays on a single platform means that a person can perform more assays in less time, with potential cost savings on human labor, Maerkl says. "If you do a back-of-the-envelope calculation and take everything into consideration, including salary costs and the cost of reagents, it is about 0.5 Swiss francs per assay," he says. "It's almost negligible."

To eliminate the need for collecting blood from people's veins, Swank and her colleagues assessed whether they could use blood samples obtained from a finger prick—a simple procedure in which a finger is pierced with a tiny needle to obtain a small quantity of blood. The researchers tested three commercially available devices to perform finger-prick blood tests, including glucose test strips used by people with diabetes to measure their sugar blood levels.

The microfluidics-based antibody test could be successfully run on blood samples collected with all three methods, even when the blood was left to dry and stored for about one week at room temperature, or when samples were shipped by regular mail from Geneva to Lausanne. The study was published in PNAS.

"The approach of collecting blood in a decentralized way by a simple finger prick that can be even done at home, and a sophisticated laboratory-based assay with high diagnostic accuracy makes this test very attractive for large-scale epidemiological studies, explains Isabella Eckerle. It could even be used for remote geographic regions that lack sufficient laboratory capacity, for example to conduct seroprevalence studies in Sub-Saharan Africa." She adds that "the small amount of blood and the collection by a finger prick, which is quick and almost painless, also makes this method very attractive for the use in children and offers a unique opportunity to assess seroprevalence rates in daycare centers or kindergartens."

Maerkl and his collaborators are now using the test to determine the prevalence of antibodies against SARS-CoV-2 among kindergarteners in Geneva, in collaboration with Silvia Stringhini and Idris Guessous of the Population Epidemiology Unit at HUG. In the future, Maerkl says, this technology could make it possible for people to buy a blood sampling kit at a pharmacy or a supermarket, collect their own blood with a simple finger prick, and mail it to a central laboratory that analyzes the blood sample and returns the test results via email or a smart-phone app.

There's no obvious limit on how many molecular assays can be done using the microfluidic diagnostics platform, Maerkl adds. "We're interested in expanding this platform to other types of assays that would detect other biomarkers that people might want to measure—for example, blood ferritin levels in people with anemia," he says.

More information:
Zoe Swank et al. A high-throughput microfluidic nanoimmunoassay for detecting anti–SARS-CoV-2 antibodies in serum or ultralow-volume blood samples, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2025289118
Posts: 3858
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

A newly developed electronic ‘nose’ could identify COVID-19-infection

6/2/21 ... ction.aspx

A faster, cheaper, and better way for COVID-19 testing

The COVID-19 pandemic has generated a surge of interest in developing rapid, cost-effective, and readily deployable detection of infections. Such measures would allow for better management of infections and better tracing capabilities.

However, despite increased research efforts attempting to increase the speed and efficacy of detecting COVID-19, the most commonly used method remains PCR testing. Although this provides accurate results, the duration, training, and setup required makes this technique potentially difficult to readily deploy on a large scale. As such, governments have focused testing efforts at key focal points to concentrate patients such as drive-throughs or large-scale testing clinics.

In a new effort led by researchers at the Weizmann Institute in Rehovot, Israel, a team led by Professor Noam Sobel, the Head of the Department of Neurobiology, is now developing an electronic-based tool to detect COVID-19 infections using a faster, cheaper, and more efficient method.

Electronic detection of infectious diseases is a long-standing concept, with research labs attempting to adapt the method to COVID-19 over the past year. The technique relies on the characterization and detection of metabolites by devices that can identify the ‘smell’ of metabolites produced by the metabolic processes of infections.

Nevertheless, COVID-19 has proven difficult to detect as it is a disease with metabolites that are particularly difficult to characterize. In response, most research has focused on lab-based methods using samples already known to be infectious, a concept that Prof. Sobel wants to overturn.

The Weizmann Institute team transitioned from lab-based to field-based testing, adjusting their methods to better adapt to more deployable strategies. The current device in testing is a plastic 3D printed tool containing a one-way valve in which patients can breathe through, similar in appearance and size to a breathalyzer, connected to a laptop. Researchers then set up at a nearby testing ‘drive-thru’ facility set up by the Israelian Red Cross, collecting data from individuals being tested immediately as they arrive.

This method can provide results within 80 seconds of testing, providing rapid and readily available infection data much faster than PCR tests currently in place with a much more reduced setup needed.

Difficulties in teaching a ‘nose’ to smell COVID-19

Data is currently being collected, analyzed, and sorted from patients which is then gathered into a COVID-19 learning program for the electronic ‘nose’ to learn to detect infected individuals. This teaching is currently in progress, and results on the effectiveness of detection may take some time.

Indeed, teaching this new device has proven difficult as the characteristic metabolite profile, or ‘smell’, of COVID-19, has yet to be found. Typical electronic detection works with a specific endpoint, a known disease profile from which the program can learn. However, the COVID-19 profile has yet to be fully characterized. This increases the time needed for the learning process as it lacks the successful endpoint that typical machine learning requires.

Nevertheless, prolonged teaching of COVID-19 detection is important to optimize identification rates, providing more accurate tests. Moreover, the field-based method of the research team provides faster, and more data than lab-based research, aiming to accelerate the learning process of this electronic ‘nose’.

Field-based methods will also provide larger datasets with key data on the individual variation of infection characteristics, such as infection levels, which in turn, will help testing facilities to better identify individuals or areas at risk.

Researchers are confident that this new tool will provide a new readily available testing method once the COVID-19 metabolite profile has been learned. Further tests remain to be conducted on the new variants emerging in different countries, yet this technique would significantly improve the speed, cost, and deployment of COVID-19 testing.


Snitz K, Andelman-Gur M, Pinchover L, Weissgross R, Weissbrod A, Mishor E, et al. (2021) Proof of concept for real-time detection of SARS CoV-2 infection with an electronic nose. PLoS ONE 16(6): e0252121. ... ne.0252121
Post Reply