here's what i found doing a seach on the web:
Why Give Blood?
Who needs it?
There are many uses for donated blood. People who have been hurt in accidents and lost blood need transfusions, as do some people undergoing surgery. Also, anemics recieve packed red cells and leukemic people recieve platelet concentrates. Plasma is used to make antihemophilic factors, and albumin to treat shock.
Who gives it?
Only 5% of Americans donate blood!
Blood Types!
38.4% have O+ blood
32.3% have A+ blood
9.4% have B+ blood
7.7% have O- blood
6.5% have A- blood
3.2% have AB+ blood
1.7% have B- blood
0.7% have AB- blood
Universal donors and recipients
Blood group O is the universal donor. Blood group AB is the universal recipient.
Requirements for Donating
Physical requirements
You must weigh at least 110 pounds and be between the ages of 17 and 66 years old. Some people older than 66 can still donate blood with thier doctor's approval.
How to prepare
Always remember to eat well the day of your donation appointment. You should not be over-stuffed, but you should definitely not be hungry. The best thing to do is eat a balanced meal with all of the food groups represented. It is a myth that a person should not eat red meat the day of or before a donation.
What Happens First?
The questionnaire
You check in with a volunteer who confirms your appointment and hands you a clipboard with a questionnaire. It asks things like your name, birthdate, and other personal information.
Then there is a list of "yes or no" questions, such as "In the past three years have you been outside the U.S. (except for Canada)?" and "In the last twelve months have you had a tattoo?" There are about 30 questions in all, and remember, they are all confidential.
When your number is called, you go into a room with an interviewer and he or she goes over the questionnaire and asks you to name the countries you have been to and what medications you are currently taking.
The volunteer also takes your pulse, blood pressure, and iron. To check your iron level, the interviewer must prick your ear to extract a drop of blood, then he or she puts the drop in a blue liquid, and if it falls through the liquid, your iron level is good.
Then What Happens?
How do they do it?
After the interview, you are given your donation bag. It looks like a plastic bag that is almost see-through, with tubes and vials attatched.
Then you are either shown to a reclining chair, or a horizontal table, and you get comfortable. Sometimes, in a reclining chair, you can have a drink with a straw while you donate. Yay!
The nurse, sometimes the same as the interviewer, looks at your arm and makes marks with a pen where the vein is.
The needle is inserted into the arm and the blood flows into the donation bag. You are given a small grip to squeeze every five to ten seconds to aid the flow of blood. When the bag is full, and this is determined by a weight scale, the needle is remobed and the nurse fills the vials attached to the bag. The blood in them is used for testing.
After the needle is removed and the puncture in the arm is bandaged, the nurse asks how you feel. If you feel light-headed or faint, you should lay down for a few more moments. When you feel okay, you go to what they call the canteen where there are drinks and cookies. You should stay there for at least ten minutes to rest and drink and eat.
It's over!
from: http://www.inform.umd.edu/EdRes/Colleges/HONR/HONR269U/catherine.html
"If God has spoken, why is the world not convinced?"
..........Percy Bysshe Shelley, English poet (1792-1822)