The American Red Cross has a significant need for type O negative blood donors.

According to a press release, type O negative blood can be transfused to patients with any blood type and is often used in emergency situations.

Eligible donors with type O negative blood are encouraged to make a whole blood or double red cell donation, where available, through the Red Cross.

During a double red cell donation, two units of red blood cells are collected while most of the plasma and platelets are returned to the donor.

Blood donation appointments can be scheduled by calling (800) 733-2767.

Those who come to donate now through May 15 will be entered to win four single-day tickets to any of 10 Cedar Fair theme parks in the U.S.