Optical methodology for rapid detection of COVID-19
Developing an optical methodology for rapid detection of COVID-19
This new methodology, whose first results are published in the journal Scientific Reports, from the Nature Group, has obtained a sensitivity of 100% and a specificity of 87.5% in the detection of SARS-CoV-2 in nasopharyngeal exudate (the same samples used in a PCR test) from symptomatic people.
It has also been possible to detect the presence of SARS-CoV-2 in fresh saliva of asymptomatic people, as well as to detect, differentiate and quantify two types of synthetic viruses (lentiviruses and synthetic coronaviruses) in two biofluids (saline solution and artificial saliva). The main advantage of this new technology over PCR lies in the speed of sample processing and the ability of the optical system to simultaneously analyze a large number of samples.
Mobile security cabin for handling biological samples developed in the C-CLEAN Project, installed in the laboratory-truck of the EOD-CBRN Specialty of the Spanish National Police.
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"We hope that the low cost will make high-performance testing more accessible locally and around the world." Lutz is senior author on a paper published Dec. 15 in Science Advances that describes the Harmony COVID-19 test kit. The researchers developed Harmony to be simple and easy-to-use, employing ready-to-use reagents. The test uses a "PCR-like" method to detect the presence of the SARS-CoV-2 RNA genome in a nasal swab sample with the aid of a small, low-cost detector, which was also designed by Lutz's group. A smartphone is used to operate the detector and read the results. The detector can handle up to four samples at a time and would fit into a standard car's glove compartment.
The accuracy of COVID-19 tests has been a pressing matter throughout the pandemic. Many at-home antigen kits for COVID-19, which detect pieces of the proteins the virus creates instead of its genetic material, are 80-85 percent accurate, though accuracy may drop with the omicron variant, which harbors a relatively high number of mutations not found in other strains. PCR tests are generally 95 percent accurate or better — a key FDA benchmark — but require expensive equipment and a long wait for results.
Initial results reported in the paper show that the Harmony kit is 97 percent accurate for nasal swabs. The Harmony kit detects three different regions of the virus' genome. If a new variant has many mutations in one region, the new test can still detect the other two. It can, for example, detect the omicron variant, which has dozens of mutations in the region of the genome that encodes the so-called spike protein.
Though tests based on PCR — or polymerase chain reaction — are highly accurate, a key limitation is that PCR tests require dozens of cycles of heating and cooling to detect genetic material in a sample. The test developed by the UW team sidesteps this issue by relying on a PCR-like method known as RT-LAMP, which doesn't have the same stringent temperature-cycling requirements.
"This test operates at a constant temperature, so it eliminates the time to heat and cool and gives results in about 30 minutes," said Lutz.
Lutz and two colleagues spun out a new company from the UW, Anavasi Diagnostics, which last year was supported by $300,000 from WE-REACH and later received $14.9 million in grants from the National Institutes of Health to develop the Harmony prototype kit into a product and scale up manufacturing to help address the ongoing shortage of COVID-19 diagnostic tests.
Initially, Lutz and his team hope the kits could be made available first for use in clinics, as well as other settings with medical oversight, such as workplaces and schools. Later, they would like to adapt the test for home use.
"For a long time, the options have been either a PCR test that is expensive and typically takes a day or more to get a result, or a rapid antigen test that gives fast results and is low cost, but typically has lower accuracy than a lab PCR test," said Lutz. "From the first day, we designed our test to be manufacturable at low cost and high volume, while delivering fast results with PCR-like performance."
The NIH funding will support high-volume manufacturing at a new Anavasi facility near Seattle.
"We plan to make our test accessible and affordable throughout the world," said Lutz.
MEDICA-tradefair.com; Source: University of Washington