Blood donors are desperately needed -- especially those with type O -- according to the American Red Cross, which will hold a blood drive Tuesday from noon until 6 p.m. at the Regions Bank location on Elm Street (at the corner of Elm, Madison and Main).

If you don't know your blood type, donating blood is one way to find out. The identification card you will receive after your first blood donation lists your blood type and could prove handy in the event of an emergency.

Although 38 percent of the population is eligible to donate blood, only 8 percent actually donates. Blood of all types is continuously needed. Locally there is less than a 36-hour supply of all blood types combined. There is less than a 24-hour supply of types A positive, A negative and B negative blood and less than a 12-hour supply of type O negative blood.

Although every blood type is important, type O donors play a critical role in maintaining the blood supply, say Red Cross officials.

Officials say 38 percent of the United States population has type O positive blood, making it the most common of the eight blood types. Since 84 percent of the U.S. population can receive type O positive blood, there is a steady demand for it from hospitals and patients. People with type O negative blood are particularly in demand because they are the "universal donor." It means that people of all blood types can receive type O negative blood safely, so it is used during life-threatening emergencies or when the matching blood type is in short supply.

In recent weeks, blood collections have fallen short 600 units due to blood drive cancellations resulting from winter weather and the flu outbreak. Because the blood supply often drops to seriously low levels during the winter months, Red Cross officials are asking eligible citizens to donate now to help patients in need.

Men and women of all blood types are welcome to donate.

In addition to whole blood, donors will have the opportunity to give double red cells. Unlike traditional whole blood donations, which are sent to the laboratory for separation into components, this process separates the donor's blood into its components as it is being drawn. The donor's plasma, which contains vitamins, minerals and nutrients in blood, is returned to the donor during the donation process, along with a small amount of saline solution. Because red cells are the component most needed for blood types O positive, O negative, A negative and B negative, double red cell donation allows a donor to give just what patients need.

If you are at least 17 years of age, weigh a minimum of 110 pounds and are in good general health, you may be eligible to donate blood. All donors need to present positive identification. For more information on blood donation, call (800) GIVE-LIFE.