Covid blood plasma donation: What is blood plasma?
It's part of a trial looking at whether it can be used to fight Covid-19.
Fourteen new donation centres are opening in England over the next few months including in places such as Lancaster and Leeds.
But what is plasma in the blood? How could blood plasma donations be used to treat people who are seriously ill with coronavirus?
BBC health correspondent Laura Foster explains
Video by Mattea Bubalo, Laura Foster and Terry Saunders.