Advent of faster, less complex COVID-19 test

Scientists have developed a new approach that is less complex and does not require extracting the genetic RNA material of the virus.

Scientists from the National Eye Institute, National Institutes of Health Clinical Center, and the National Institute of Dental and Craniofacial Research have developed a faster method to prepare samples to detect the SARS-Cov-2 virus.

This new less complex approach, they reported, does not require extracting the genetic RNA material of the virus, thus simplifying the purification process, which may translate to reduced time and money. They reported their results in iScience.1

The virus currently is detected during a process that involves collecting a samples using a nasopharyngeal swabs, storing the swabs during transport in a viral transport medium, RNA extraction, and quantitative reverse transcription polymerase chain reaction (RT-qPCR).

The investigators reported using a chelating resin, Chelex 100 (Bio-Rad), during their method to preserve the virus RNA that was collected via nasopharyngeal and saliva samples, thus simplifying the preparation of the sample.

This approach eliminates the need to extract RNA during the testing for the virus.

Direct detection RT-qPCR and digital-droplet PCR were performed and the results compared with the conventional method during which RNA is extracted for simulated samples and patient specimens.

The investigators found that “heat treatment in the presence of Chelex markedly improved detection sensitivity compared to heat alone, and lack of RNA extraction shortens the overall diagnostic workflow.”

Another plus is that the heating renders SARS-CoV-2 incapable of causing infections, which improves the safety surrounding the processing of the swabs by the laboratory technicians.

“This fast RNA preparation and detection method is versatile for a variety of samples, safe for testing personnel, and suitable for standard clinical collection and testing on high throughput platforms,” the investigators concluded.

Reference
1. Guan B, Frank KM, Maldonado JO, et al. Sensitive extraction-free SARS-CoV-2 RNA virus detection using a chelating resin. iScience 2021; published August 8; https://doi.org/10.1016/j.isci.2021.102960