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SCIENCE REPORT – Dec. 27: Giving Blood Platelets
By Nancy Steinbach
This is the VOA Special English Science Report.
People all over the world know the importance of giving blood to help people who have lost
blood because of an accident or operation. There is also a(one) need for the part of the
blood called platelets.
Platelets are cells in the blood that help stop bleeding by permitting the blood to become
thick, or clot. Taking platelets from a person’s blood is done in a process called apheresis
Blood is taken from a blood vessel in a person’s arm through a tube. The blood is passed
through a machine called a centrifuge. The machine separates the platelets from the other
parts of the blood and collects them. The machine returns the other parts of the blood
to the person’s arm.
This process takes about two hours. A person’s body replaces the donated platelets in about
forty-eight hours. One person can give platelets up to twenty-four times a year.
Almost all healthy people can donate their platelets. A person must be older than seventeen
years of age and weigh at least fifty kilograms.
However, some people with medical conditions should not donate platelets. People should
not donate platelets if they have ever suffered hepatitis or cancer or have heart problems.
People should not donate platelets if they have had malaria or lived in an area where the
disease is present in the past three years.
Women who have been pregnant in the past six months should not give platelets. Blood
donation programs also will not accept blood products from people who may have been infected
with the AIDS virus.
And the programs will not accept blood products from people who have visited countries
where mad cow disease is present.
Blood centers always need platelets because donated platelets must be used within five
days. People who are having treatments for cancer need blood platelets. Radiation and
chemotherapy treatments lower the number of platelets in their blood. So they must get
platelets to prevent bleeding.
Experts say the demand for platelets continues to increase as more people are getting cancer
treatments. The strong government controls to guarantee the safety of blood products have
also limited the supply of platelets in recent years.
This VOA Special English Science Report was written by Nancy Steinbach.