Thermo Fisher, the largest maker of scientific tools, said Friday it plans to produce up to 5 million kits of a new test to detect the novel coronavirus that causes Covid-19.

The company, based in Waltham, Mass., plans to reach that level of production by the week of April 3, according to Ron O’Brien, a company spokesman.

The Food and Drug Administration granted the new test an emergency clearance late Friday.

Before Friday, the U.S. had struggled to increase its capacity to test for the virus, a key step in trying to limit the damage of the pandemic it is causing.