A team of researchers has helped develop a Covid-19 testing device that can detect coronavirus infection in as little as 30 seconds as sensitively and accurately as the polymerase chain reaction (PCR) test, the gold standard of testing.
According to a recent peer-reviewed study published by the University of Florida group, like PCR tests, the device is 90 per cent accurate, with the same sensitivity.
It could transform public health officials' ability to quickly detect and respond to the coronavirus, or the next pandemic.
"There is nothing available like it," said researcher Josephine Esquivel-Upshaw from the University of Florida.
However, it is not yet approved by the US Food and Drug Administration.
First, researchers said, they have to ensure that test results are not thrown off by cross-contamination with other pathogens that might be found in the mouth and saliva. These include other coronaviruses, staph infections, the flu, pneumonia and 20 others. That work is ongoing.
The hand-held apparatus is powered by a 9-volt battery and uses an inexpensive test strip, similar to those used in blood glucose meters, with coronavirus antibodies attached to a gold-plated film at its tip. The strip is placed on the tongue to collect a tiny saliva sample. The strip is then inserted into a reader connected to a circuit board with the brains of the device.
If someone is infected, the coronavirus in the saliva binds with the antibodies and begins a dance of sorts as they are prodded by two electrical pulses processed by a special transistor. A higher concentration of coronavirus changes the electrical conductance of the sample. That, in turn, alters the voltage of the electrical pulses.
The voltage signal is amplified a million times and converted to a numerical value - in a sense, the sample's electrochemical fingerprint. That value will indicate a positive or negative result, and the lower the value, the higher the viral load.
The device's ability to quantify viral and antibody load makes it especially useful for clinical purposes, researchers said.