BloodCenter of Wisconsin has issued an emergency appeal for blood donors because of the lower than normal donations following the July 4 holiday week.

Several blood types are at critically low levels, less than a half day supply, according to a BCW news release. BCW strives to maintain a two- to three-day supply to ensure that life-saving blood is available to treat patients in need.

“We look to our volunteer blood donors for this precious, life-saving resource during times of critical need,” Jerome Gottschall, M.D., senior medical director, BloodCenter of Wisconsin, said in the release. “This time of year we need them more than ever. We need them to know they are saving lives and making a difference in our community. It’s donations that are made today that will help save the lives of people tomorrow.”

Donors can schedule an appointment at any of BCW’s 10 statewide donor centers or at one of its community blood drives by calling 1-877-232-4376 or visiting versiti.org/Wisconsin.