A glass plate contains roughly 2.5 million micro test tubes per square centimeter. (Provided by Rikiya Watanabe)

Researchers developed what they claim is the world’s fastest diagnostic testing method for the novel coronavirus, a procedure that takes less than 5 minutes.

A team led by Rikiya Watanabe, a chief researcher at the Riken national research institute in Wako, Saitama Prefecture, plans to quickly develop equipment for the method and start a clinical trial by the end of March 2023.

Polymerase chain reaction (PCR) tests are widely used in Japan to check for infection, but it takes at least an hour before the results are known because the method involves a process that amplifies the coronavirus’s ribonucleic acid (RNA), which stores genetic information of the virus.

The new method does not require this step.

An antigen test can directly detect the protein that is characteristic to the virus and takes only 30 minutes or so to provide results. But it is less accurate than the PCR method, and false-positive and false-negative cases are frequently reported.

The new testing method, called CRISPR-based amplification-free digital RNA detection (SATORI), uses an enzyme that activates when detecting the RNA.

Under this method, the “shell” of the virus in saliva and other biological samples taken from patients is cleaved off and mixed with the enzyme in solution.

The solution is then placed onto a plate comprising micro test tubes to check for a molecule that glows when the enzyme is activated. When light from the molecule is detected, it means the virus is present.

The method can detect the virus within 5 minutes even if the amount is very small by checking the reaction inside micro test tubes with a capacity of one-trillionth of 3 milliliters each.

Costs per test are almost the same as the PCR method, according to a research team member.

The findings were published in the online version of Communications Biology, a journal affiliated with the British scientific magazine Nature, on April 19.