Blood donors are in high demand as centers rush to replenish the supply shortage caused by Hurricane Sandy.

About 3,000 units of blood went uncollected in the Philadelphia area due to the storm, said Anthony Tornetta, communications manager for the American Red Cross.

He says, nation-wide it's about 11,000 units, or more than 300 blood drives that were canceled.

"We're definitely relying on the community," said Tornetta. "It's going to be a long process, it's not something we're going to get back in a day."

Tornetta says the Red Cross is reaching out to potential donors by making calls and sending messages.

Orli Gal from Philly came in to donate blood because of one of the reminder calls.

"I really hope it helps people like the ones that were evacuated from that hospital in New York," Gal said. "I can only imagine that their whole blood supply was ruined if their generator was broken down. I hope [to help] replenish that and help anybody who was injured badly in the storm."

But Tornetta say it's likely Gal's blood will stay in Philly.

If there is a need though, blood units will be shipped to harder-hit areas.

In the meantime, the Philadelphia blood donor center is running on extended hours and to replenish their low supply.

You can go to the American Red Cross website to find information on blood donations or other relief efforts through the organization.