Tanise Martin had not been able to shake a feeling of helplessness since the coronavirus pandemic began its deadly march through her community, which has been hit particularly hard. So when she learned about a blood bank just a few miles from her apartment in Prince George’s County, she decided to volunteer.

The six hours Martin spent at the Seat Pleasant Volunteer Fire Department in early May, when Maryland law enforcement officer Kendal Wade and the American Red Cross teamed up to host a blood drive, made Martin feel proud for the first time in months.

“I know how important it is to stay at home right now, but I am just so happy I can finally help,” said Martin, 27, who has been unable to teach her preschool students online. “Every time someone was able to give blood, I felt like celebrating.”

While scores of blood drives were canceled amid the initial shock of the novel coronavirus outbreak, donation centers have since managed to recruit and sustain a steady flow of donors and volunteers such as Martin. But the capacity to generate donations will be tested in the coming weeks, as elective surgeries resume across the country and demand grows for convalescent plasma — a component of blood from previously infected individuals used in coronavirus treatments.

“As surgeries open up, we are putting that cry out to get donors,” said Erin Goodhue, executive medical director for the American Red Cross. “We want everyone to know that we have put protocols in place to keep people safe.”

The national blood supply had been decreasing for a decade before the pandemic hit around early March, which led to the cancellation of more than 4,000 blood drives across the country. The American Red Cross still managed a surplus by late March because nonessential medical procedures were put on hold, shutdowns or stay-at-home orders kept people out of emergency rooms, and volunteers nationwide showed up to donate blood.

As states have begun to relax some of these restrictions, blood banks will be under strain to fulfill the increased demand. As of early May, patients in states including Maryland and Virginia can schedule elective procedures such as tumor removals and orthopedic surgeries. These patients with upcoming transfusions are dependent on fresh blood for survival, Goodhue said. Platelets, the cells in blood that help it clot, are only viable for five days after collection. Red blood cells, the most commonly transfused blood component, expire after 42 days.

In the past three weeks, orders for blood products have increased threefold in the Washington region, according to Nicholas Lilly, director of Inova Blood Donor Services. That means that the Virginia organization, which collects blood to distribute to local hospitals, needs to recruit 200 donors per day to meet the need, all while limiting the number of people in its donation centers.

“We greatly appreciate the community efforts of our neighbors so far,” Lilly said. “But we need that support to continue.”

Donation centers across the country have extended their hours and scheduled more appointments to meet the demand generated by elective procedures under social distancing protocols.

At the donation drive Wade helped organize in Prince George’s County, volunteers, phlebotomists and donors wore masks and maintained distance, and donors had to pass a temperature check.

“We took extra precautions to make sure everyone was safe,” Wade said.

The precautions are similar at donation sites across the country. At centers run by Inova Blood Donor Services, even the prepackaged candy that donors receive after giving blood is dispersed about every six feet.

“It is important that centers everywhere have implemented social distancing measures and taken steps to make sure donors remain safe,” said Eduardo Nunes, vice president of science and practice at AABB, an association representing blood centers, labs and hospitals. “But it impacts the volume of collections and cuts our capacity significantly.”

Some blood donor services, such as Inova, have had to maintain their donor flow without mobile test sites, which were a central part of their operations before the pandemic. They are, at least for now, relying entirely on brick-and-mortar locations, which can limit community outreach. Other centers have continued mobile test sites with neighborhood partners while mitigating flow.

OneBlood, which serves hospitals in Florida and North Carolina, has partnered with such groups as the YMCA to host blood drives in parking lots. The American Red Cross is hosting drives out of hotels and places of worship, in addition to standard donation centers.

Blood donation centers must also contend with the increased demand caused by the interest in convalescent plasma, which is collected from individuals who have recovered from the novel coronavirus. Medical experts hope antibodies contained in plasma from recovered patients will help those who are fighting severe symptoms of covid-19, the disease caused by the virus.

“We are eager to do work with plasma because it allows us to contribute and pitch into the fight against the coronavirus,” Nunes said. “But it is not a core function of blood centers. Our environment works best when we have well-defined and homogenous protocols in place.”

Blood donation centers are implementing a variety of strategies to help manage different types of donors. Inova Blood Donor Services has sequestered areas within donor centers for those who have recovered from the coronavirus; they must be symptom-free and negative for the virus before donating. The American Red Cross is collecting convalescent plasma at more than 170 locations nationwide, according to Goodhue.

As summer months near, a traditionally low donation time for blood centers, medical experts are counting on volunteers to maintain an adequate supply while hospital visits are expected to soar. A deficiency in the national blood supply may leave the country unprepared for a mass casualty event and patients deprived of lifesaving treatments.

Medical experts encourage potential donors to go online to the American Red Cross or the sites of independent blood centers to find locations where they can give.

“The need for blood never stops, not even for a pandemic,” said Abby Fueger, a clinical trial nurse navigator at the Leukemia and Lymphoma Society. “A delay in treatment could mean patients are not getting the treatment that they need.”