Researchers in Sweden and China have collaborated to develop a test for covid-19 that can be performed without advanced laboratory equipment and deliver the result in about half an hour, according to a recent study.1
The researchers—from the Karolinska Institute, Shenyang University of Chemical Technology, and Huazhong University of Science and Technology—adapted a technique called loop-mediated isothermal amplification (LAMP) specifically for the novel coronavirus SARS-CoV-2. The technique makes it possible to amplify the virus’s RNA at a constant temperature of 65° C and to see a reaction in only 20 to 40 minutes.

“One big advantage with our test is that it is fast, and you can perform it under basic conditions,” says Vicent Pelechano, PhD, a researcher at the Karolinska Institute and one of the study’s authors. “All you need is a test tube containing the primers, a hotplate, a thermometer, and a pot of water. This makes it especially suitable for regions that lack advanced analytical equipment, such as war-torn areas or refugee camps.”

By combining primers optimized specifically for SARS-CoV-2 with a specific gene of the virus, the researchers were able to detect as few as 10 copies of the virus gene, which is in line with the detection limits of polymerase chain reaction-based tests. The technique can be combined with a pH indicator, which changes the color of the reaction mix from pink (alkaline) to yellow (acidic) if the sample is positive for SARS-CoV-2.

“The color-indicator makes it extremely easy to see if a sample is positive or negative,” Pelechano says. “That could be a decisive factor if you lack specialized equipment to check the reaction.”

The researchers are now working on verifying the test results on confirmed covid-19 patients at the Karolinska University Hospital.

Reference

1. Yu L, Wu S, Hao X, et al. Rapid detection of covid-19 coronavirus using a reverse transcriptional loop-mediated isothermal amplification (RT-LAMP) diagnostic platform. Clin Chem. Epub April 21, 2020; doi: 10.1093/clinchem/hvaa102.