The blood supply in the United States is much safer today than ever before. The risk of HIV transmission is extremely rare and the risk of hepatitis transmission greatly reduced thanks to multiple levels of safeguards, including:comprehensive evaluation of donors' medical and social history to exclude donors who may be carriers of infectious agents; physical examination of the donor; strict donation procedures using sterile supplies; laboratory testing. These procedures are followed by all blood centers nationwide and are monitored under the regulatory guidance of the U.S. Food and Drug Administration.

Blood donors are not paid; only volunteers are permitted to give blood. Community volunteers are the safest source of blood for transfusion. Every donor completes a health history questionnaire and screening interview to identify behaviors that indicate a high risk for carry blood borne diseases. Strict confidentiality encourage honest answers and deferral of any potential donor with possible health risks.

Many infectious diseases (including AIDS, hepatitis, syphilis, malaria, and others) may be transmitted from blood donors to patients. However, laboratory tests are performed on every unit of blood collected. Every time someone donates blood, his or her unit of blood is tested for evidence of infectious disease, including HIV, hepatitis B and C, and syphilis. Any unit of blood that shows evidence of carrying a disease is discarded and the donor is deferred from subsequent donation. The donor's blood type is also determined and a complimentary cholesterol screening is performed (results are available online or by telephone).