MCALLEN – With summer approaching, Rio Grande Valley blood centers are concerned about the shortage of donors.

About 2,500 units are needed every month in order to supply the demand.

In summer, without high schools in session, they lose their biggest contributors.

High school students can bring in between 30 to 40 percent of the blood donations.

When there isn't enough to serve those patients, blood is imported from other centers across Texas.

Valley blood centers also host smaller blood drives in order to keep up with demand.

Watch the video above for more information.