Hi doctors, can you tell me what is involved in plasma donations?

All vs component: Whole blood donation collects red cells, plasma, platelets--which can be separated and used. Plasma collection (/apheresis) uses a machine to separate reds / platelets from carrier fluid--golden ylw fluid (/plasma). The cells are returned to you in saline (salt water) and the plasma is collected. Plasma can be donated every 28 days.