Quick test: US scientists have developed a method that can be used to determine whether a patient is infected with the Sars-CoV-2 virus in less than three quarters of an hour. The test uses the Crispr gene editing tool.
The Crispr-Cas9 process was only developed a few years ago. It offers the possibility of cutting a genome strand at a very specific point and inserting other genetic information at this point. Doctors hope to use it to develop treatment methods for certain diseases that have so far not been successfully combated.
Researchers at the University of California at San Francisco (UCSF) and the biotech company Mammoth Biosciences are using the process to create a Ribonucleic acid (RNA) in a sample. RNA is a genetic strand like deoxyribonucleic acid (DNA), but consists of only a single strand. The researchers programmed the Crispr system to recognize two sequences in the genome of the Sars CoV-2 virus.
One of the sequences occurs in all Sars-like corona viruses, the other only in Sars-CoV-2. By searching for both sequences, the researchers ensure that the test distinguishes between Sars-CoV-2 and related viruses.
As usual, the sample is taken from the patient's nose or throat. The result of the test is determined after around 40 minutes. It can be read on a test strip comparable to a pregnancy test. The usual one on the Polymerase chain reaction (PCR) based test takes about four hours.
The Crispr-based test, which the developers called Detectr, detects the virus with an accuracy of 95 percent: Detectr identified 38 of 40 samples that were confirmed as positive, which corresponds to an error rate of 5 percent. As a cross-check, the researchers also used Detectr to test 42 samples that had been confirmed as negative. None was wrongly identified as positive. Detectr needed according to the developers no complex laboratory equipment.
The researchers led by Charles Chiu from UCSF and Janice Chen from Mammoth Biosciences describe their results in an essay in the journal Nature Biotechnology. They are currently trying to get approval for the test from the Food and Drug Administration (FDA), the U.S. Food and Drug Administration.