Canadian Blood Services says it is in “urgent” need of donors before the Labour Day weekend.

Specifically, the organization says it needs more than 22,000 donations of blood prior to Aug. 26.

Elaine St. Pierre, a territory manager with the organization, told CTV News Channel that vacations and back-to-school preparations can leave the country at risk of a blood shortage.

“The summer is a particularly slow time for donations, with many of our regular donors away or busy,” she said Tuesday.

Type O-negative blood is especially in demand because it is compatible with all other blood types, meaning it is often used in hospitals for emergency transfusions.

“Giving blood is a lifesaving habit that will make a real difference in a stranger’s life,” Rick Prinzen, Canadian Blood Services’ chief supply chain officer, said Monday in a statement. “If every donor brings a friend to donate, or encourages others to give life, they can have a tremendous impact on the supply system.”

Blood donation appointments can be made via the Canadian Blood Services website, through the GiveBlood app or by calling 1-888-2-DONATE. All clinics also accept walk-in donations.

A number of changes to donor eligibility requirements came into effect this year to make it easier for people to give blood.

“Some people that may have thought they couldn’t donate blood before … may actually be eligible,” St. Pierre said.

One of the biggest differences is that the waiting period to donate after receiving a tattoo or piercing has dropped to three months from six. Additionally, donors no longer after to wait 12 hours after intoxication to give blood, as Canadian Blood Services now accepts donations from anyone who is sober.