Thousands of missed appointments across Canada — some due to flooding in Alberta — have prompted Canadian Blood Services to put out a call for donors.

Between June 12 and July 18, about 12,000 appointments were missed or cancelled.

The Alberta floods also had an impact. Clinics had to be cancelled in Calgary and other communities affected by flooding.

"What we’re doing now is  we’re putting a call out to people," said Canadian Blood Services spokeswoman Deb Steele-Kretschmer.

"If you haven’t donated blood yet or if you’ve always been thinking about donating, now is the time to book an appointment."

Blood products last between five and eight days so the national supply constantly needs replenishing, she said.

People can donate at permanent clinics in Edmonton, Calgary, Lethbridge and Red Deer and mobile clinics across the province.