Let me briefly explain the situation. There is no effective public organization for obtaining and distributing blood here. If someone needs blood for an operation, they need to get it somehow through friends or family. Thus, when the unfortunate situation occurs where it is needed, friends and family have to scramble to get volunteers to go into the hospital or clinic to collect the blood, and have that blood designated for the patient. Volunteering merely to give blood to the system is possible, but it is almost never done. Argentineans do not like giving blood for whatever reason, so obtaining the necessary amount can be very problematic.
This is a direct and practical way you can help. Unlike giving money or goods to charities, which many studies have proven of dubious value for various reasons, your blood will be used for what it was intended for, for life and health.
Be prepared to spend most of the morning in confusion, uncomfortable surrondings, in crowds and bring a good book and dress in your rough clothes as you may want to sit on the floor. I hope that I don`t sound too negative about the experience of giving blood here, I just want to dispel any idea that it was as easy as in some other countries in North America or Europe, so that whoever decides to try it would stick it out. Many come here with the notion of getting a taste of life in Argentina or to help a charity, but this is a practical way we can help.
You can just generally donate at hospitals or clinics, or you can look for requests in the newspaper ads or public notice boards. Often an "obra social", a private health provider for subscribers, will have a tent in a plaza getting relatively quick donations, although the blood wouldonly then go to its members.
A friend of mine who has lived here for 3 years went to donate blood. her Spanish is pretty good, but they refused her because it's not her mother tongue and they were concerned that she wouldn't understand the paperwork she was signing.
In Argentina you also cannot donate blood if you have a tattoo (in other countries you can now, as long as you've had hep screenings).