Julie,
my doctors told me that blood turns to its initial quantity three months after a surgery, but returns its quality a bit longer - 6 months are needed. So when i would like to donate blood for my granfather had to have a surgery 2 months after mine, i was not allowed to.
I asked the House Ear clinic if i have to donate blood in advance in case they need it for my surgery, but they replied that blood will be taken from Red Cross banks so no need me to do it.
It is not the case in my country Bulgaria, though. Since here a lot of people are reluctant to donate, when someone goes for a surgery doctors ask his/ her relatives to donate - this is the only way to make people donate here - which sucks, i know.
Me personally, have never been allowed, however, because I have always been less than 50 kgs and they say that to donate you have to be 50 - 55 kgs.
do kgs matter in the US?
Hrissy