GIVING BLOOD IN ORANGE COUNTY

Only about 20% of all the blood Red Cross collects is used as whole blood, which has a shelf life of 42 days. These are the major blood products:

RED CELLS are used for about 70% of all blood needs.

Shelf life: 42 days (Can also be frozen and stored for three years, but once reconstituted they must be used within 24 hours. The freezing-reconstituting process is costly and is used primarily for preservation of rare blood.)

Diameter: 7 microns (1 micron=0.0000039 inch) Number: 4 million-6 million/microliter (0.00003 ounce)

WHITE CELLS can be obtained by a special pheresis procedure from a specially recruited donor who gets the red cells and plasma back after the white cells have been extracted. Platelets may also be obtained by pheresis when a large quantity of matched platelets are required for a particular patient.

Shelf life: less than eight hours

Diameter: 7-12 microns

Number: 4,000-10,000/microliter

PLATELETS are required for clotting and are used in cancer treatment and for bleeding problems.

Shelf life: 5 days

Diameter: 2-4 microns

Number: 150,000-400,000/microliter

PLASMA can be frozen and stored for up to a year, or it can be processed into antihemophilic factor, serum albumin or gamma globulin, all products in high demand.

Source: American Red Cross, Los Angeles-Orange Counties Blood Services Region; World Book Encyclopedia