LA CROSSE, Wis. (WKBT) -

 The Red Cross is preparing for a possible blood shortage this summer.

The organization is expecting a drop in numbers this summer now that school is ending. They made the plea Thursday on World Red Cross Day.  

Blood drives on college and high school campuses make up about 20 percent of donors. 

In the summer, the number of 18 to 24 year-old donors drops in half. 

However, it's not just end of the school year that has the organization concerned.

"Another thing that plays into blood donation in terms of the need is the actual shelf life of blood, and I'm not sure everyone is aware of that. Red cells themselves have a shelf life of about 42 days, and the platelet component which are often used for cancer patients and so forth, the shelf life there is just five days," said Red Cross Recruitment Rep. Scott Friell.

To find out how to donate, you can call 1-800-RED-CROSS or visit their website at www.redcrossblood.org