On Point: Inside the for-profit business of selling blood plasma around the world. Kathleen McLaughlin: "If you go to the Red Cross... you are limited to donating 13 times a year, once every 28 days,&quot. And what is plasma used for, and why is it a big, largely hidden business? And then there are ways to donate the blood as whole blood, usually through volunteer donor programs. And so there is a difference there.