SIOUX FALLS, S.D. (AP) — Sanford Health says a critically ill patient has received a transfusion of plasma from a recovered coronavirus patient, the first use of the therapy by the health care provider. Sanford’s treatment is part of a national clinical trial to test the effect of blood plasma in treating COVID-19.

The use of plasma is for hospitalized patients with severe cases of coronavirus. The plasma may lessen severity or shorten the length of the illness caused by the virus. Because the therapy is still considered experimental, the plasma is being administered under a program led by Mayo Clinic. Sanford’s first patient receiving the therapy is in Fargo, North Dakota.