Jeremy Hobson: Today is a particularly important blood drive day at many American Red Cross centers. That’s because the Red Cross is short on blood. Donation levels in May and June were at the lowest levels in a dozen years.

Marketplace’s Adriene Hill reports.

Adriene Hill: When you donate blood, you’re doing good. No doubt about it. But when you sit down and a nice lady sticks that needle in your arm, you’re letting her drain away some pretty valuable stuff. Take a unit of red blood cells, which is about a pint.

Dan Waxman: Now, in the United States, it’s over $200.

Dr. Dan Waxman heads America’s Blood Centers, a group of independent blood banks. Centers, including his, and the Red Cross, are nonprofits. They depend on volunteers for blood donations. But they charge hospitals for that donated blood.

Waxman: Blood centers must be able to offset for their expenses.

They’ve got to pay staff, run tests, rent space. And the cost of blood goes up again at the hospital. A recent study found patients pay about $340 a unit.

Of course there’s also a value for the donator. Stephanie Millian is with the Red Cross.

Stephanie Millian: Their incentive is knowing that they’re helping someone in need.

And maybe they’ll get a cookie.

I’m Adriene Hill for Marketplace.