Why is there a minimum weight limit on giving blood?

Question

I Want to give blood but you have to be 7st 12 and i am not, why does your weight affect you giving blood?

Answer 1

In the US it's 110 pounds.

Answer 2

because lighter smaller people have less blood to give than taller bigger people.

when they take blood they take it in a certain amount if your small you cant meet that amount since you can fill up a bag or UL likely depending on the cercom stances black or pass out

Answer 3

A person with a lower weight will feel the effects of loosing blood easier.  Their blood pressure will drop resulting in passing out and possibly hurting themselves.

Answer 4

When you donate blood, you give a standard amount--one pint.  (Plus they take a little more for testing purposes.)  They don't adjust that based on size, for the most part (sometimes in special cases, like one sibling donating to another when there is a rare blood type and both are children, they make exceptions).

Smaller, lighter people have less blood overall, so taking the standard amount from them is more likely to cause side effects (dizziness, nausea, drop in blood pressure, fainting) than in people who are larger--it's a question of its being a larger percentage of the total blood volume.