MARSHFIELD, Wis. -

The BloodCenter of Wisconsin is bracing for a blood shortage this summer, when donations traditionally drop by about 20 percent.

That's mainly because blood drives at high schools and universities shut down with students on break.

Vicki Bohman helps run the BloodCenter's donor center in Marshfield. She told News-Herald Media the shortage could cause problems for hospitals that rely on the center's donations.

Bohman said the BloodCenter must collect about 800 units of blood each day to meet the demand at 59 hospitals statewide. A shortage could be especially challenging for places like Ministry Saint Joseph's Hospital, which receives all its donated blood from BloodCenter of Wisconsin sites.

To encourage donations the BloodCenter is giving out free tickets to the Central Wisconsin State Fair at upcoming Marshfield blood drives.