Blood supplies are critically low - meaning a day or less before running out - in several blood types, said John Helgren, spokesman for the Blood Alliance, a nonprofit community blood bank that supplies area hospitals.
The shortage locally and in other parts of the U.S. stems from the growing gap between those needing blood and flagging donations.
"This is one of the more critical shortages that we've experienced," Helgren said.
The three blood types most affected are O negative, O positive and B negative. Other blood types are also in low supply but not yet at perilous levels.
"This is a big deal because we're sitting on the edge of our seats concerned that we won't have enough blood to deal with a bad trauma," said Colleen Higgs, transfusion service supervisor at Shands Jacksonville, the city's only trauma center.
If a hospital runs out of blood, it needs to get it from another hospital. That can be time consuming and puts a patient's health at risk. Hospitals in the area share blood on a first-come, first-serve basis when the supplies are low.
C. Daniel Smith, chairman of surgery at the Mayo Clinic, said cardiac surgeries have been put off in the last few days because doctors weren't satisfied with the amount of blood available.