Low blood donations plaguing the U.S.

Thousands of blood donation appointments are available across the country, including in Arizona. But if things keep going the way it has since May, not many people will be signing up.

Vitalant, which provides blood to hospitals and other health care services, says the current blood supply available for patients is down 25%. The most critical blood types needed are O positive and O negative, which are both considered nearly universal types.

Vitalant says the recent low is due to the summer season, where there are less blood drives and more people on vacation.

Blood donations overall have been hit in recent years. The American Red Cross had issued a National Blood Crisis last year. And this year, they have seen 50,000 fewer donations than needed in the last two months.