Difference between Negative and Positive blood?

I while back I donated blood, and i got a letter from the blood bank, saved a boy named Jesse.

I found out i am A- , actually don't know what that means, could someone explain that to me?

 

http://www.infoplease.com/ipa/A0877658.html

 

If youre A- you will always be negative.

 

in simple terms, + or - describes the presence of certain 'markers' on your blood cells. Your body uses these markers to identify your blood cells from foreign cells. In general there are three types of markers. If you are type A, you have 'A' markers. If you are type 'B', then you have 'B' markers. And if you are +, then you have the third type of markers.

Your body can only take blood with less markers than it has, because if it sees a blood cell with extra markers, it recognizes that cell as foreign and will try to kill it, which is dangerous for the person. That's why O- can donate to anyone, since it has no markers at all. On the other hand AB+ can donate to no one except itself, since it has all markers. But AB+ has the benefit of being able to receive from any type.

 

by markers, i hope you mean antigens

OP, type O is universal donor. It doesn't contain A or B antigens so your body will not produce antibodies to attack them (which is why anyone can accept this type)

 

It's easier to explain antigens as markers, because people don't understand what antigens are or what they do.

 

Lol I want to be on a news article