You may be disqualified from donating if you're 17 years old or younger or weigh less than 110 pounds; you're pregnant; you've traveled to an area with a malaria risk in the last year; or you've had a tattoo or piercing in the last 6-12 months. There are health and lifestyle markers that may also disqualify you from donating as well. Additionally, you also have to pass a blood prick test that checks for anemia and protein levels.