Information, extraction and testing
Safeguarding the quality of uniform information for donors and blood banks was a lengthy process. Approved blood donors who had had COVID-19 were encouraged to donate plasma. The blood banks provided details of the project on their websites and the media helped to inform the public. Many donors reported recovery from COVID-19 when they were called on to donate blood, and some were recruited through Koronastudien.no. Other convalescents who met donor requirements were accepted at some blood banks. Ensuring that blood bank staff were rapidly informed of constantly changing rules was a challenge. Several blood banks lacked procedures for plasmapheresis, and there was uncertainty about the requirements for shipping blood samples to other laboratories for antibody testing.
Several blood banks lacked procedures for extracting plasma
According to the first recommendation from the European Centre for Disease Prevention and Control, there should be a delay of at least 14 days between a positive SARS-CoV-2 PCR test in a respiratory sample and convalescent plasma collection. After the discovery of virus particles more than two weeks after the first positive PCR test in some individuals in early May 2020, the Norwegian Directorate of Health prolonged this to 28 days. Most potential plasma donors therefore had to wait 28 days before the first antibody test.
Plasma was harvested in three ways: by plasmapheresis, where up to 650 mL of plasma is collected while the blood cells are returned to the donor; in a whole blood donation, where red blood cells and platelets are used for the production of ordinary blood components (giving 200–250 mL of plasma); or by thrombapheresis, where the main product is platelets and 400–500 mL of plasma is collected as part of the procedure, while red blood cells are returned to the donor. Following plasmapheresis, the donor was invited to three more procedures at least one week apart. Donors with sufficient antibody levels were encouraged to undergo a new series of donations after a few weeks.
In Norway, the only whole plasma product in current use is a chemical pathogen-inactivated, mixed plasma from approximately 1000 donors. In cases of COVID-19, convalescent plasma is transfused from individual donors, which increases the risk of transfusion-related acute lung injury (TRALI). The recommendation was therefore to use donors who had not been transfused or women who had never been pregnant, or to test donors for antibodies against human leukocyte antigens (HLA). Plasma from donors with HLA antibodies was not used to treat patients.