Novel positive controls offer several advantages over the ones currently used in COVID-19 testing.
As rapid COVID-19 tests are being used more and more to deliver faster results to people, there is a growing need for a foolproof way to determine that they work correctly and that the results they give can be trusted.
Investigators from University of California San Diego have now developed nanoparticles that are similar in quality to coronavirus particles which can serve as a positive control for COVID-19 tests. The results from the study were published in the journal Biomacromolecules.
A positive control is a test sample that always produces a positive result. They are run and analyzed with the patients tests and are used to verify that a test is working as consistently and reliably as it should.
The team behind the study used an earlier version of positive control for RT-PCR tests. The newly developed controls are able to be used on a more affordable, easier to use and faster test called RT-LAMP. RT-LAMP, coupled with the novel positive control, could help begin rapid, mass testing of COVID-19 in underrepresented areas where access is not up to standards.
The controls that were developed are tiny virus shells made of plant virus or bacteriophage and houses COVID-19 RNA inside of it. The segments used include binding sites for both PCR and LAMP tests.
"This design creates an all-in-one control that can be used for either one of these assays, making it very versatile," Soo Khim Chan, a first author on the study said.
The two types of positive controls are very sturdy, and protect the viral RNA from breaking down at warmer temperatures. This allows them to be stored for longer periods of time at temperatures up to 40 degrees Celsius.
The team plans for future research and to partner up with industry leaders to implement their new technology.
"With mutants and variants emerging, continued testing will be imperative to keep the population safe," Nicole Steinmetz, the lead researcher on the study said. "The new technology could find utility in particular for at-home tests, which may have a higher rate of false readouts due to the less controlled experimental conditions."