Amid a critical blood shortage, one of the nation’s largest blood services is now providing antibody tests to donors, free of charge.

Amid the critical shortage, one of the nation’s largest blood services is now providing antibody tests to donors, free of charge.

It’s a critical shortage,” said Cliff Numark, chief of marketing for Vitalant, an independent, nonprofit blood collector that services hospital patients in New Jersey from Bergen County to Ocean County as well as in the New York region.

Vitalant is the first blood bank in the country to provide coronavirus antibody testing to donors, according to a statement.

“It performs very well in this area,” he said, noting that it is a lab-based test that has shown to perform well with both “sensitivity” and “specificity,” two factors that measure testing accuracy.

Numark noted that antibody testing is also critical for obtaining convalescent plasma, which can be used as a potential treatment.

Those who have recovered from COVID-19 have antibodies in their plasma — a component of their blood — which “can be given directly to patients currently battling COVID-19 to help boost their ability to fight their illness,” Numark said in the statement.

Though antibody tests don’t guarantee immunity to the virus, people may be eligible to donate in the future, the statement said.