The U.S. Department of Health and Human Services granted $4 million in emergency funding to a San Diego biotech company working on a way to keep the Zika virus out of the nation’s blood supply.

The main concern is someone donating blood and not knowing they are infected.

Hologic created an automated Zika test, mostly done by hand. The test is said to be sensitive enough to detect any Zika in the blood.

The company is in the process of shipping out almost a million tests.