On top of knowing that she had only 1 kidney, yes only one since birth, she still carry on the liver donation. Liver and kidneys are essential organs that remove the toxic from the body. And if i know that i have only 1 kidney and 3/4 of a liver left, i might not perform the op for someone that i do not know.
(i read somewhere that an average weight of the liver is 2kg, thus to donate 500g leaves 1.5kg of liver, which is 3/4)
Certainly a courageous woman to go ahead with the liver donation.
More info on her blog
The posts on her liver donation (below)