Plasma Donation and COVID-19 Plasma donation is a specific form of blood donation whereby plasma, the clear liquid component of whole blood, is collected during donation through a process known as plasmapheresis. During plasmapheresis, an apheresis machine removes and separates the plasma from the whole blood. As plasma contains nutrients, proteins, and antibodies, it can be used to develop treatments for diseases. Plasma used for these purposes is called convalescent plasma. A bag of blood plasma. Image Credit: Pavel Kosolapov / Shutterstock.com Convalescent plasma has been used in the prevention and treatment of infectious diseases for centuries. It is considered a form of ‘passive immunization’ as plasma collected from patients who have recovered from a previous infection and developed adaptive immunity, demonstrated by the presence of antigen-specific antibodies. Upon transfusion into another patient, the plasma can neutralize the disease pathogen, eventually eradicating it from blood circulation.