The Blood Supply Banks
To ensure the safety of the blood supply, blood banks in the United States thoroughly check each unit of blood for infection and carefully screen the donors.
Before they donate, all volunteers are asked for an extensive medical history to reveal potential exposure to disease risks. The history includes questions about foreign travel, high-risk sexual activity and intravenous drug use. The screening process is conservative to exclude anyone who might have been exposed to a blood-borne disease. For example, people who have traveled recently to an area where malaria is common will be temporarily excluded, even if they show no signs of the disease.
Other safety measures are enforced as well. For example, blood donation in the United States is voluntary and without pay, to decrease the chance that patients at risk for blood-borne diseases would conceal facts about their lifestyle or travel history so that they could receive payment for donating blood.
After giving blood, donors have an additional chance to exclude themselves by confidentially requesting that their blood not be used. That allows participation at times when donating blood seems obligatory, such as at a workplace drive or when a family member is ill.
Check the Follow Blood Supply
The next level of safety involves the quality of the blood itself. Every unit is put through a battery of tests to check for hepatitis B, hepatitis C, HIV (the virus that causes AIDS), HTLV-1 (a retrovirus similar to HIV) and syphilis. There are actually three tests for HIV, for more accurate testing of patients who have contracted the disease recently. With this combination of tests, anyone infected with HIV would test positive within approximately 10 days of infection, as opposed to the six months that had been standard. In addition, most blood donors give repeatedly, and therefore are tested repeatedly, decreasing the risk that they could transmit a blood-borne illness.
To keep blood transfusions as safe as possible, new tests for infectious agents are constantly evaluated. Potentially transmissible diseases may be a high priority for concern either because of their seriousness (transmissible spongiform encephalopathies such as “mad cow disease”) or their prevalence (West Nile virus infection). Next the blood test developed to screen for the disease must be proven to be very effective.
Despite extensive testing and safety measures, the system is not foolproof. There’s still a risk — albeit extremely slight — of developing a transfusion-related disease. For example, the risk of acquiring HIV from a transfusion is approximately one in 500,000 to one in 1 million for each unit of blood received. These numbers are considerably lower than in 1987, when the American Red Cross estimated a risk of about one in 150,000. In addition, some rare diseases, such as malaria, can slip through simply because we are unable to test for them.
Reducing The Risk of Blood Supply
In an emergency situation, the slight risk of infection from donated blood is often dwarfed by the potentially lifesaving benefits of the transfusion. Moreover, if you are facing elective surgery, you can reduce the risk of transfusion-related disease to the vanishing point by donating blood to yourself. (See Your Own Blood Supply. )
In the future, other risk-reducing options may become available. Researchers are investigating recombinant technology as a way of creating pharmacologic treatments that may be just as effective as human blood components. Scientists also are working on ways to sterilize platelets and red blood cells with techniques similar to those currently being used to sterilize blood plasma. That would yield blood transfusions that had been cleared of all known viral activity and bacteria.
Another step you can take if you’re facing surgery is to find out whether your hospital is accredited by the American Association of Blood Banks. All hospitals and blood banks are inspected by the FDA, but the AABB also conducts a voluntary inspection and offers certification to topnotch facilities. Nearly all blood centers and about two-thirds of hospitals belong to the association. Call the blood bank at your hospital and ask if it’s accredited by the AABB. If it’s not, discuss your safety concerns with your surgeon, and ask if there’s an accredited hospital you can use instead.
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