Based on a reaction between yeast and the novel coronavirus, the test will rapidly detect the presence of SARS-CoV-2 in saliva and will be available by mid-2021 (Credit: BIOinFOOD)

A rapid COVID-19 diagnostic 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.

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. 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.