"Another way researchers are trying to bring testing to the masses is to devise assays that could be used in temporary testing facilities, drive-through testing centres and even in people’s homes. At least two teams are taking advantage of the gene-editing technology CRISPR to power such tests. For example, researchers led by Zhang have developed a coronavirus assay that can be run in a single test tube in about an hour4. But it still requires heating the sample to about 65 °C, and it’s not as sensitive as a PCR-based assay. “That’s okay, because it’s much easier to use,” Zhang says. When tested multiple times on samples from 12 people infected with coronavirus, the assay detected the virus on nearly every occasion. The test builds on an approach that Zhang co-developed in 2017, called SHERLOCK5, which relies on the ability of the CRISPR machinery to home in on specific genetic sequences. Researchers program a guide molecule to latch on to a particular stretch of the SARS-CoV-2 genome. If the guide molecule finds a match, a CRISPR enzyme generates a signal that can be detected either as a fluorescent glow or as a dark band on a paper dipstick (see ‘Cut and detect’). On 6 May, the US Food and Drug Administration (FDA) authorized a SHERLOCK coronavirus assay for emergency use. The test is made by biotechnology firm Sherlock BioSciences in Cambridge, Massachusetts (of which Zhang is a co-founder), and the company has partnered with a manufacturer to mass-produce the kits. (See also ‘Coronavirus assays assessed’.)"