MODEL RELEASED. Donated blood being checked by a technician in a hospital laboratory. Donated blood is stored for a short time, after which it is destroyed if it is not used. All blood and blood products is checked for infection, which could indicate a donor that is unsuitable. The notice at far right shows the differences that the technician needs to look out for when checking blood bags. Donor blood is given to patients in transfusions to replace lost blood, for example during surgical procedures or after accidents.