A return to a somewhat normal summer as COVID-19 restrictions are eased is putting a strain on Canada's blood supply.

Several provinces have started lifting restrictions and demand is up as a result.

"As provinces slowly open up, there's some return to normal activities," says Tracy Smith with Canadian Blood Services. "Hospital demand is increasing."

Smith says you can imagine that they are trying to catch up with some of the backlogs and some of the surgeries that were put on hold during the pandemic. This is placing greater demand on blood products.

The need for blood tailed off dramatically 16 months ago 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 was not able to accommodate as many donors because of physical-distancing requirements at clinics, so the two balanced each other out.

About 400,000 of Canada's 37 million population give blood on a regular basis.

Canadian Blood Services operates a national inventory that allows products to be regularly shifted around the country to meet hospital and patient needs.

But the 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.

Smith says the blood agency has made some changes in anticipation of an increased need, including extending hours at some donation centres and mobile clinics, but many pandemic safety precautions remain in place, including limiting the number of donors allowed inside at one time.

"We're only accepting appointments from donors, we're not accepting walk-ins in order to manage our physical distancing," says Smith. "It's more important for donors to fill the appointments for us."

Smith can not say how much the demand for blood has increased in the last six weeks, but she says the need is evident in supplies of O negative blood, the universal blood type used primarily in emergency rooms.

"We have just over four days supply and at times it's dipped to between three and three and a half," she says. "That gives you an indication of the increase in demand that we've seen."

The next blood donor clinic in Steinbach is at Steinbach Mennonite Church on Monday, August 2nd.