Each day life-saving blood transfusions are needed in hospitals and emergency treatment facilities across the U.S.
There are more than 9.5 million blood donors in the United States and an estimated 5 million patients who receive blood annually, resulting in a total of 14.6 million transfusions per year.(Source: NBCUS, 2007 [PDF - 2.11 MB)
Most patients do not experience any side effects from blood transfusions. On rare occasions, blood transfusions can cause adverse reactions in the patients receiving blood.
Although the U.S. blood supply is safer than ever before, some bacteria, viruses, prions, and parasites can be transmitted by blood transfusions.
Each donor is screened for risk of transmissible disease by questionnaire, and each unit of blood donated in the U.S. is routinely screened for various infectious disease pathogens, including five transfusion–transmitted viruses, using nine laboratory tests.
All blood is tested for evidence of certain infectious disease pathogens, such as hepatitis B and C viruses and human immunodeficiency virus (HIV).
As of 2003, the estimated risk of contracting HIV per unit transfused in the United States was estimated at between 1 in 1.4 million and 1 in 1.8 million units.
The United States' blood supply is considered extremly safe, but globally, the numbers show a more dangerous picture. 75 million units of blood are estimated to be donated annually, compared with 13 million donations in the United States. Of the 191 WHO member states, only 43% test blood for HIV, hepatitis C, and hepatitis B viruses.
Source: Centers for Disease Control and UCSF