Canadian Blood Services says it is struggling to replenish a critically low national supply caused by the COVID-19 pandemic.
The organization says the virus that has persisted since March 2020 has resulted in the smallest donor base in a decade.
"The number of people across Canada who donate regularly has decreased by 31,000 donors since the start of the pandemic, which has put a strain on the existing donor community," said Rick Prinzen, chief supply chain officer and vice-president of donor relations for Canadian Blood Services.
"Many of our regular donors already donate multiple times a year."
The service oversees the inventory from which blood and blood products are regularly shifted around the country to meet hospital and patient needs.
About 400,000 Canadians give blood on a regular basis.
But inventory has a shelf life — a year for frozen plasma, 42 days for red blood cells and five days for platelets — so it takes some work to ensure supply continues to meet demand.
Canadian Blood Services is hoping that National Blood Donor Week on now will help attract 100,000 new donors this year. But summer is a traditionally slow time for donations as people cancel appointments or go on vacation.
"Right now, we have compounded losses in donors due to COVID-19 and not having the ability to recruit new donors at in-person community events because of restrictions over the past two years," Prinzen said.
"Patient lives depend on new donors coming forward."
The need for blood products tailed off dramatically as the pandemic brought travel to a near standstill and all but the most critical surgeries were cancelled.
At the same time, Canadian Blood Services wasn't able to accommodate as many donors because of physical-distancing requirements at clinics, so the two balanced each other out.
But with things returning to normal, demand is increasing, Prinzen said.
Eric Polo, 15, from Toronto receives blood products every month for a rare condition that affects his body's production of red blood cells.
"They keep me alive," he said.
"I am thankful for what blood donors do."