Coronavirus tests are now more available. But a key testing component is in short supply.

A new shortage of a key testing component is hobbling the U.S. battle against COVID-19 as the number of confirmed coronavirus cases continues to rise.

Earlier testing was marred by problems that produced potentially inaccurate results. Now, as U.S. testing ramps up, some labs have run short on the kits and components needed to determine whether samples taken from ailing patients confirm the presence of the novel coronavirus.

The problem is emerging as the number of confirmed COVID-19 cases in the U.S. rose to 1,050, with 29 deaths, as of Wednesday morning, according to Johns Hopkins University.