How safe are blood transfusions?

If you are in a serious accident or require major surgery, there's a good chance you'll need a blood transfusion. Donor blood saves lives, but receiving a transfusion carries risks. Here are some safety concerns involved with blood transfusions that you should know.

The short answer is no. Thanks to improvements in methods for screening donors and blood, the risk of infection from transfusions is tiny.

• News reports of people who developed exotic and terrifying conditions such as West Nile and mad cow disease after receiving transfusions have called attention to the problem of tainted blood.
• It will never be possible to safeguard the blood supply against all infectious diseases that emerge, but there's comfort in knowing that scientists are able to respond to new threats rapidly by developing effective screening tests.
• For example, scientists discovered in 2002 that West Nile virus can be transmitted through blood transfusions. (The disease may cause a range of symptoms, from headaches and fatigue to high fever and convulsions.) In response, the US Food and Drug Administration collaborated with industry and blood collection groups to develop new screening tests for donors. In 2003, blood testing laboratories began using those new tests to screen the blood supply.

What's more, rigorous screening of donors and superior testing methods have dramatically reduced the threat to the blood supply from more common infectious diseases over the past two decades.

• For instance, the risk of receiving blood infected with human immunodeficiency virus (HIV) or hepatitis C is roughly one in 2,000,000. (The odds of being struck by lightning in a given year are about one in 700,000.)
• There's also little danger of acquiring cancer from donated blood. A 2007 study by Swedish researchers showed about three percent of blood donations come from people who have undetected cancer. However, recipients of their blood do not have an increased risk for any form of the disease.

Patients may have reactions — ranging from itching and fever to hives and nausea — to blood that's not their own. But the most worrisome threat may be what's in the blood that shouldn't be. Understandably, you may have some concerns so keep this guide in mind and contact your doctor for more information.