The closure of schools and many businesses has meant the cancellation of hundreds of blood drives, putting pressure on the region's blood banks.

"This is unprecedented in the history of the Red Cross," said Carrie Carlson-Guest of the American Red Cross Minnesota Region.

Since the arrival of COVID-19, 295 Red Cross blood drives in Minnesota and the Dakotas have been canceled, resulting in an estimated loss of 9,800 donors.

Blood drives are an essential component of the voluntary blood-collection system, and many organizations sponsor them as a form of community service.

While the number of people who participate in drives may vary, it is unusual to have so many drives canceled in a short period.

"Over half of the blood that we collect comes from drives," said Erica Buege of Memorial Blood Centers, Minnesota's other large nonprofit blood bank.

"High schools and universities are huge supporters of ours," she said. "They host blood drives for students and staff all the time."

Be The Match, which relies on volunteers for bone marrow transplants, has also been significantly affected. It relies on college events — now canceled — to recruit potential donors for its registry. And it has faced difficulty making arrangements for matched donors because of travel restrictions and canceled flights.

Memorial has not compiled data on how many of its drives have been canceled, but immediately after schools closed about 60 drives were called off.

Minnesotans continue to donate blood at blood bank offices, and some drives are proceeding at businesses that are open, keeping the supply adequate for now. But with reduced collection capacity, hospitals are keeping a close eye on inventory.

"This is the most worried we've ever been," said Dr. Lauren Anthony, system laboratory medical director at Allina Health.

Blood is used in many different ways. Some of it gets broken down into components, including plasma, red blood cells and platelets, each with a different shelf life. While plasma can be frozen, platelets have a shelf life of just five days, and by the time they get to a hospital they often have to be used in three days.

"If there are no donors today then in four or five days we could have a shortage, so the need for platelet donors needs to be constant because they can't be stockpiled," Anthony said. "We always have to be thinking three to six weeks ahead."

Even though hospitals are postponing elective surgeries, the demand for platelets is not falling because they are needed for patients whose care can't be delayed, including cancer treatment and heart or emergency surgery. Platelets are needed to form clots that stop bleeding.

Be The Match relies on what are known as "live drive" events to sign up people.

"We recruit about 400,000 donors a year," said Amy Ronneberg, acting CEO. "This is definitely going to have an impact on our organization."

For now, Be The Match is trying to pivot to social media campaigns as an alternative.

The more pressing problem happens when a donor is identified for a patient who needs a transplant. They are asked to visit a clinic or a hospital to get a physical exam.

"There certainly has been an increased fear of going into a hospital right now," Ronneberg said. "So what we've seen is donors afraid to step forward if they get the call."

Others who want to donate often can't. Donors can come from thousands of miles away and from foreign countries. Travel restrictions have made it difficult for the organization to move people. Be The Match did get permission from the federal government to let donors in, but so many flights have been canceled that the organization is considering chartering private jets using financial donations.

So far, though, Be The Match has been able to complete all 130 transplants scheduled last week.

Blood banks say they've taken extra precautions to space donors apart at donation offices. Donors' and staffs' temperatures are taken before they enter, and everything is wiped down. But even before the COVID-19 pandemic took hold, people with cold or flu symptoms were turned away from donating.

With the new stay-at-home order taking effect, giving blood is considered an essential service, so traveling to give blood is permitted.

The blood banks recommend that interested donors call ahead or schedule an appointment online. Because appointments have been filling up, it might take a week to 10 days to find an available spot.

"It is important for the public to know that giving blood is safe and we are taking additional precautions amid the COVID-19 pandemic," Buege said.

Glenn Howatt • 612-673-7192

Twitter: @GlennHowatt