CINCINNATI — Low temperatures and school closings have resulted in blood supply shortages in southwest Ohio, health officials say.

The Hoxworth Blood Center at the University of Cincinnati said seven of its scheduled blood drives were canceled last week as frigid weather closed local schools and businesses.

Five of the canceled blood drives were scheduled for high schools. About 14 percent of the center’s collections come from high schools within its 17-county region of southwest Ohio, northern Kentucky and southeast Indiana, said spokeswoman Alecia Lipton.

“Weather really impacts us when schools close,” she said.

The blood center estimates it has 65 percent of its optimal supply for serving its 30-hospital region. Although all blood types are needed, Lipton said the supply of A-positive is at an emergency level.

The weather, flu cases and general apathy have caused low donor turnout for the past month, said Dr. Ronald Sacher, director of the blood center.

“We are in a state of emergency for all blood types and need the community to support our efforts in securing a healthy blood supply,” he said in a statement.