A nationwide blood shortage has reached Hawaii, leaving some patients waiting for transfusions they urgently need — bad news for anyone facing surgery, trauma, or an emergency.

• Blood donations fell to a four-year summer low, and the American Red Cross has declared only its second-ever blood crisis.
• Hawaii's supply has dropped to half a day at times, far below the three-day cushion blood banks aim to keep.
• Providers are flying blood in from the mainland — one Big Island patient's plasma had to come from Iowa.
• Blood expires, so it cannot be stockpiled; supply depends on a steady stream of donors showing up.
• Only 2% of eligible people in Hawaii give blood, and raising that by one percentage point would cover most of the need.

Outlook: Without a jump in local donations, Hawaii will keep depending on costly out-of-state shipments and patients will keep waiting.