I try and donate blood as frequently as possible through the American Red Cross
The ARC is truly a humanitarian organisation. I  would prefer  to donate and volunteer my time if I have the chance
They do such great things.  Unfortunately, I'm unable to donate my time, but I would love to do that too
The good thing about ARC is that they are affiliated to the   International Federation of Red Cross and Red Crescent Societies and the United States movement to the International Red Cross and Red Crescent Movement so I'm sure every or anything donated will be judiciously used 
That is my hope.  I hater hearing about charities that only donat a dime out of every dollar to the causes they are supposed to be supporting.
The ARC does other stuff as well such as services to the public and development initiatives and programs
I have never had a bad experience with them while giving blood.  It's really the least that I could do.
Thats amazing, it would interest you that the first president of the ARC was a woman. Clara Barton