Although the nation’s blood supply is safer today than ever before, many people remain fearful of catching AIDS or another disease from a transfusion.
For an update on transfusion safety, we spoke with Dr. Edgar G. Engleman, who pioneered the testing of donated blood for the AIDS virus in the early 1980s.
According to Dr. Engleman, the blood supply is now remarkably safe, especially when compared with 10 years ago. Risk of catching a serious infection is roughly one in 5,000. There are several explanations for this increased level of safety
Widespread screening
In the early 1980s, donated blood was screened only for hepatitis B and syphilis. Not until 1985 was testing for the AIDS vims (HIV) implemented on a nationwide basis.
Most blood banks did not launch efforts to screen for AIDS prior to the availability of a specific test, arguing that the risk of catching AIDS from a transfusion was tiny and the cost high. In fact, up to 2% of the units of blood transfused in some cities in the early 1980s harbored HIV. Thousands were needlessly infected, including Arthur Ashe and Ryan White.
Today, the Food and Drug Administration keeps close watch over blood banks. It doesn’t hesitate to close down those that don’t follow regulations.
More accurate HIV testing
At one time, blood banks tested only for the presence of antibodies to HIV (not the vims itself). Problem: It can take a while after infection for antibodies to form. There is a window of time when a person’s blood is infectious even though the vims aren’t detectable via conventional antibody testing.
To offset this problem, more sensitive antibody tests have been developed.
Result: The window has shrunk from 24 weeks to about four weeks. In addition, die FDA has licensed a test for HIV itself. This test, which is mandated for use by all blood banks, shrinks the window even further.
And prospective blood donors are thoroughly questioned about possible risk factors for AIDS (homosexuality, intravenous drug abuse, etc.) before they are allowed to donate blood.
Bottom line: Roughly one in 400,000 transfusions now results in transmission of HIV. The new test should reduce the incidence to one in 700,000.
Fewer transfusions are given
A generation ago, doctors recommended transfusions even in cases that weren’t life threatening to help people feel less tired after surgery, for example.
Today, doctors order transfusions only to save lives not to make patients feel better.
Beyond aids screening
Blood banks now screen donated blood for the two strains of HIV, syphilis, hepatitis B and C, plus two other potentially deadly pathogens
- Human T-lymphotropic virus (HTLV-1 and HTLV-2). Close relatives of HIV, these viruses cause cancer and other illnesses.
- Cytomegalovirus (CMV). It can cause a life-threatening infection in premature infants, chemotherapy patients, and AIDS patients, transplant recipients taking immune-suppressant drugs and other individuals with poor immunity. Diseases for which we are not yet testing, but which may be cause for concern, include
- Hepatitis G. This newly discovered strain of hepatitis is less virulent than other strains but more persistent.
- This one-celled organism (protozoan) causes chronic infection, which can lead to heart failure.
As more people enter the US from areas where Chagas is endemic (chiefly Central and South America) the incidence of the disease in the US will increase. Even so, the number of cases spread by transfusion will probably remain low.
How to avoid bad blood
What can individuals do to protect themselves from tainted blood? First, it’s important to remember that blood transfusions save lives and that people have died because they refused transfusions. Having said that, there are ways to minimize your risk…
• Pre-deposit your own blood
Autologous donation banking your own blood is the single most significant precaution you can take. Barring human error in the handling of your blood (extremely unlikely), your risk of contracting a transfusion-related illness is essentially zero.
• Recycle your blood.
Many operating rooms are now equipped with “cell-saving” devices that collect blood draining from the surgical incision and reintroduce it into the body.
Called intraoperative autologous transfusion (IAT), this technique is often effective in emergency surgery so it’s definitely worth asking for. It cannot be used for intestinal surgery, tumor removal or any other operation in which blood could be contaminated with bacteria or cancer cells.
• Know your options
In California, surgeons are required to inform patients of their transfusion options. This is not the case in all states.
If your surgeon doesn’t explain your options, ask him to do so. Alternatives should be discussed at least six weeks before surgery.
If significant blood loss is expected, a series of autologous donations may be required over several weeks. Blood cells can be stored for up to 42 days, frozen plasma for up to one year.
The surgeon isn’t necessarily to blame if you should need a transfusion. However, you’re likely to lose less blood under the hands of a good surgeon. Ask how many times he/she has done this procedure.
Some hospitals can provide plasma or platelets taken from one person. “Single donor” blood is generally less likely than “pooled” blood to carry disease. However, this isn’t always practical. Given today’s careful screening practices, the increase in safety is marginal at best.
Some patients scheduled for surgery ask friends and relatives to donate blood. The assumption is that blood from someone you know is safer than blood from anonymous donors.
In fact, friends and relatives are likely to be first-time donors (whereas the community supply consists mostly of blood from repeat donors), so their blood hasn’t been subjected to repeat testing. Ironically, it may be less safe.
• Ask about blood-boosting drugs
Researchers have identified hormone-like substances that spur the production of red blood cells, white blood cells or platelets. In many instances, these factors can be synthesized using recombinant DNA technology and used as drugs.
Erythropoietin (EPO), one of the first of these to become commercially available, helps the body make more red cells. It’s helpful for some patients with kidney failure and other chronic conditions that used to require repeated transfusions.
However, since the body takes up to a few weeks to manufacture blood cells in response to the EPO, its value in surgery is limited.
