Canadian Blood Services is calling on donors to book and keep appointments as it faces a decrease in collections.
The organization says it currently has only four days worth of O+ blood type supply and five days worth of O- and B- blood types, along with six days worth of A- blood type and seven days worth of A+ and B+ blood types.
Spokeswoman Delphine Denis says collections have been steadily decreasing since July 1.
She says ongoing illness and isolation requirements related to COVID-19, heat-related weather issues and the return of pre-pandemic activities and summer travel that have left many people with less time to donate are all factors contributing to the situation.
The organization says the number of people who donate blood regularly decreased by 31,000 donors during pandemic, leaving it with the smallest donor base in a decade.
It says there are 57,000 open appointments that must be filled before the end of August across Canada.
Denis says donors from all blood groups are urged to book appointments to donate blood right away or over the next few weeks leading up to Labour Day weekend.