Concomitant plasma is an “extra” plasma product that may be collected when a donor is undergoing an apheresis procedure for a different blood product (such as red blood cells or platelets). This method of collection of plasma for transfusion is becoming much more common in modern blood banking practice (some also call it “concurrent” plasma). You can’t walk into a transfusion service and ask to see their supply of “concomitant plasma,” however! The plasma collected in this manner generally is frozen within a required time frame and labeled as fresh frozen plasma (FFP). It is used pretty much exactly the same way as FFP derived from whole blood.