What You Should Know
Blood Transfusions
Safety
RECEIVING A BLOOD TRANSFUSION:
WHAT EVERY PATIENT SHOULD KNOW
How many Americans
need blood each year?
Nearly five million Americans receive blood transfusions each
year. Blood is used to save the lives of patients who need surgery
or other medical treatment, for trauma victims of accidents and
burns and for patients with cancer, hemophilia, and other serious
diseases.
Why would my doctor recommend that I receive blood?
You may need to receive blood in order to stabilize a medical
condition or to save your life. The amount of blood that is given
to you is a decision your physician will make based on your particular
needs. Details about why you may need blood will be best explained
by your doctor.
What steps are taken to make sure that the blood patients
receive is safe?
There are many safeguards on our national blood supply to ensure
safe blood for patients. First, blood is donated by volunteer
donors. Before giving blood, donors must answer questions about
their health and risk factors for disease, and only a person with
a clean bill of health can give blood. Blood from each accepted
donor goes through extensive testing. In addition to tests for
blood type, nine separate screening tests are run for evidence
of infection with hepatitis, HIV, HTLV and syphilis. Finally,
a carefully identified blood sample is tested against blood from
the patient who will receive it, a process called crossmatch.
What are the risks of receiving blood?
If a blood transfusion is indicated during a surgical procedure
or other medical treatment, the risks of NOT receiving blood far
outweigh the risks of transfusion. Some patients may experience
minor changes in the body's immune system after a transfusion,
causing mild symptoms, such as fever, chills or hives, which typically
require little or no treatment. A small number of patients may
also react to donated blood by developing antibodies (immune reactions).
The transmission of disease and the destruction of red blood
cells occur only very rarely, and seldom threaten life. The potential
risk of contracting AIDS from a blood transfusion has received
a great deal of attention. But it is important to know that all
donated blood in the United States is tested for the AIDS virus,
reducing the risk to a negligible level. When you consider the
risks of transfusion, it may be helpful to know that many common
activities carry far greater risks — for example, smoking
cigarettes, driving a car or being pregnant.
What can I do to make sure that a safe supply of blood
will be available should I, my friends, family or members of my
community need it?
It is very important that healthy Americans
donate blood. This will guarantee that a safe and adequate blood
supply is available for patient care. Millions of lives are saved
each year because of the availability of donated blood.
Do I have choices other than receiving blood from the
community blood supply?
Yes, you may have other choices. Autologous blood transfusion
refers to procedures in which you may serve as your own blood
donor. In preoperative autologous donation, your blood may be
collected and stored before a scheduled surgery if blood use may
be required. In intraoperative and postoperative autologous transfusions,
blood lost during surgery is saved and returned to the patient.
Directed donations can also be arranged in some cases from a person
(usually a friend or relative) whom you select.
How can I find out more about blood?
Ask your doctor for more information about your medical treatment
and the possible use of blood.
Why is blood transfused?
Transfusions are given to replace blood lost during surgery,
to replace blood lost because of accidents, and to replace blood
lost due to internal bleeding caused by a condition such as stomach
ulcers. Transfusions are used in the treatment of cancers such
as leukemia and to treat different types of anemia such as sickle
cell disease and thalassemia.
Is there a charge for receiving blood?
All blood centers and hospitals charge a processing fee to cover
service costs such as donor recruitment; collecting, testing,
packaging, storing and distributing the blood; and administrative
and staff costs. In the hospital, there are charges for matching
and administering a blood transfusion. Most health insurance policies
cover these fees.
Are there any risks in receiving a transfusion?
As with any medical procedure, blood transfusions carry some
risk. There is a remote chance of receiving blood of the wrong
type. In addition, several infectious diseases can be transmitted
by blood transfusions. Among the viruses that may be transmitted
by blood are: human immunodeficiency virus (HIV), the virus that
causes AIDS; human T-cell lymphotropic virus (HTLV-I); several
hepatitis viruses; cytomegalovirus (CMV), and West Nile virus
(WNV). However, the very small risk of acquiring such a virus
is outweighed by the benefits of a blood transfusion that is needed.
What steps are taken to reduce the risks involved in
receiving a transfusion?
Steps to ensure maximum transfusion safety involve both donor
and recipient. Donors are screened very carefully using a detailed
questionnaire for health problems or circumstances that increase
risk of transmitting infection. After blood has been drawn, it
is tested for numerous viruses and other potentially harmful disease
agents, and positive or doubtful units are discarded. Donor blood
is tested for ABO, Rh and the presence of possibly dangerous blood
group antibodies. After the recipient's blood has been tested
for ABO, Rh and the presence of blood group antibodies, donor
units are selected that lack antigens that might react with any
antibodies present in the recipient. Additional checks are then
performed to compare the specific donor unit selected with the
patient's blood.
What steps are taken to reduce the risk of acquiring
hepatitis from transfusions?
First of all, donors are questioned extensively about possible
exposure to hepatitis and behaviors that put them at increased
risk for hepatitis. Individuals who are found to have had an exposure
or a risk factor are deferred from donation. In addition, several
tests are used to detect the presence of hepatitis B and C. Since
the 1970s, all donor blood has been tested for direct evidence
of the hepatitis B virus. Since 1986, all donated blood has been
screened for indirect evidence of hepatitis B, using a test for
one of the antibodies to hepatitis B (antibody to hepatitis B
core antigen). A test for antibody to hepatitis C virus is also
in place. Hepatitis A is very rarely transmitted through blood
transfusion.
What is cytomegalovirus (CMV)?
CMV is a common virus that causes a mild to unnoticeable infection
in healthy people. About half of the adult population in the United
States has been infected with CMV. The virus can be transmitted
by blood transfusion. Although it is not a problem for most transfusion
recipients, it can cause serious disease in patients whose immune
systems function poorly, such as premature infants and patients
who have undergone tissue or organ transplantation. These patients
frequently are given blood that has been screened or processed
in such a way as to reduce the risk of CMV transmission.
What is human T-cell lymphotropic virus?
Human T-cell lymphotropic virus, type I (or HTLV-I) is considered
a leukemia virus; it differs from the virus that causes AIDS (HIV).
HTLV-I is found particularly in Japanese people and in people
living in the Caribbean area. HTLV-I can, on occasion, cause leukemia
and a paralytic disease of the nervous system, but it takes many
years to do so.
Are tests done to detect venereal disease?
Yes. Blood is tested for evidence of syphilis infection.
What other donor screening for infectious diseases is
done?
Donors who are at risk of transmitting malaria are screened
by medical history and rejected as blood donors. As a result,
very few recipients of blood transfusions in the United States
develop malaria. Similarly, individuals known to be harboring
other infectious diseases are deferred or rejected as blood donors.
How have tests performed on donated blood affected the
supply?
Blood and components are tested to eliminate units that may
carry HTLV-I, -II, HIV, hepatitis B and hepatitis C, as well as
those that are positive for syphilis. Approximately 1.7 percent
of whole blood units are discarded due to positive tests. False
positives may occur due to the sensitivity of the testing procedure.
This means that some units of blood are discarded, although the
donor does not have a viral infection. It is very important that
units that are true positives not be used for transfusion. Until
more research is done to perfect testing procedures that will
detect only true positives, blood banks and donor centers will
continue to take precautions to ensure the safest blood supply
possible; this will include not using blood with a false-positive
test result.
Has there been any progress in developing blood substitutes?
Blood substitutes with the ability to carry oxygen have been
used in animals and to a limited extent in humans. Most blood
substitutes have not been proven totally safe or completely effective.
These substitutes do not provide clotting factors or white cells
to fight infection. Most blood substitutes under development remain
highly experimental, and none has been licensed for use in the
United States. Research into substitutes is continuing, however.
The American Association of Blood Banks (AABB), through its nearly
2,000 institutional and about 8,000 individual members, is committed
to ensuring a safe and adequate blood supply for the American
people. AABB continually takes steps to enhance safety by evaluating
new technology as it becomes available. AABB assesses and, when
the specific technology is deemed effective and feasible, promotes
implementation of new technology at the blood bank level through
its Standards for Blood Banks and Transfusion Services.
As a result of AABB's development of a multi-layer safety system,
which includes donor screening, donor deferral, and testing, transmission
of transfusion-transmitted diseases has diminished steadily over
the years.
Standards
The AABB has systems in place that ensure continual review and
refinement of its voluntary standards. A standing committee is
assigned to review and update the entire publication of AABB
Standards for Blood Banks and Transfusion Services every
18 months. Interim standards may be issued to reflect new technologies,
methods, or criteria for donor selection if it is determined,
based upon available data, that they will enhance the safety of
the blood supply during the intervening periods.
Systems for ensuring the safety of the blood supply generally
are described as having five layers, which work together to screen
out infectious agents. Every blood collection center follows essentially
the same requirements, all of which are specifically set forth
in the AABB Standards. AABB standards (for which compliance is
required of members) are based upon established best practices
and in accordance with FDA regulations and guidelines.
Layer 1: Blood Donor Screening
Efforts are made to recruit volunteer blood donors only from
the safest and most suitable donors. For example, blood is collected
from universities and workplaces, but not from prisons. Blood
for transfusion is collected from volunteer blood donors. Improper
donor incentives and coercion, which could alter the truthfulness
of some donors, are prohibited.
Layer 2: Individual Screening
Each individual blood donor is required to read information
about blood safety and is encouraged to leave, without explanation,
if he or she recognizes that giving blood would be inappropriate.
Potential donors are also asked a series of questions about their
health and lifestyle (including direct questions on sexual behavior
designed to identify high-risk activities) and undergo a miniphysical
before being allowed to donate. The questions and examinations
are designed to prevent individuals who are at high risk for HIV,
hepatitis and other infectious diseases from donating blood. This
process is continually refined in order to ensure that blood is
drawn from the most appropriate individuals.
Layer 3: Laboratory Testing
The third layer involves testing collected blood for possible
infectious diseases. Nine laboratory tests for different infectious
diseases are currently conducted on each unit of donated blood.
All results must be negative for a blood unit to be labeled and
released. Tests for hepatitis B and syphilis were in place before
1985. Since 1985, the following tests have been implemented: HIV-1
and -2, HIV antigen, HTLV-1 and -2, two tests for hepatitis B
and a test for hepatitis C. Nucleic acid amplification testing
(NAT) employs a form of testing technology that directly detects
the genetic material of viruses like hepatitis C and HIV. An investigational
NAT to screen for West Nile virus is now available.
Layer 4: Confidential Exclusion
Blood donors may be offered a confidential opportunity to exclude
their blood from use in transfusion by attaching stickers to the
paperwork identifying the collected unit for use or withdrawal.
If a donor knows of any reason why his or her blood should not
be used for transfusion, he or she places the sticker indicating
that the unit should not be transfused on the label. This is done
to ensure that no pressure is exerted on the donor to give blood.
Layer 5: Donor Record Checks
Every donation is checked against existing records. If a donor
has been indefinitely deferred, the collected unit is withdrawn
from circulation and potential use. This process acts as a barrier
to prevent the release of any blood from a donor who was previously
judged to be indefinitely unacceptable.
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