Someone who donates blood is not directly tested for sexually transmitted diseases (STDs) during the donation process, but the blood is screened for some diseases that are sexually transmitted, WebMD states. In addition, screening questions look into the donor's sexual history.
Before donating blood, the donor answers questions about unprotected sex. If their answers indicate that they cannot safely donate, the phlebotomist may not take their blood. Individuals who are at high risk of HIV cannot donate blood. All blood donations are screened for some diseases that are sexually transmittable. This includes HIV/AIDS and hepatitis C. If these STDs are present, the blood cannot be used.