The big 'B' goes for blood

The need for blood is enormous -- it could be needed for road traffic accident or burn victims, heart or kidney surgeries and also for patients suffering from cancer, leukaemia, thalassemia or other diseases. Many patients died due to wrong blood transfusion process until beginning of last century. In 1901 Karl Landsteiner, an Austrian scientist, discovered human blood groups and blood transfusions became safer after that. For this recognition he was rewarded the Nobel Prize in Medicine in 1930. Although, majority of our healthy population do not donate Blood -- we are more and more becoming conscious about blood donation in Bangladesh. If we desire we can donate blood even at our places of work. There are several centres in the city where blood donations can be made. And even though a growing number of blood banks have found blood donation to be safe and practical -- we need to change present screening and donation procedures in different places.

Any person above 17 years in good health with a standard weight is suitable to donate blood. Besides this, all donors should also pass the physical/medical history examinations prior to donation of blood. At present in our country, many people other than volunteer donors provide blood, which is very risky. The donor's body refills the fluid lost from donation within 24 hours. It usually takes about 60 days to replace the lost red blood cells (RBC) and whole blood can be donated almost once every eight weeks or 60 days. In developed countries 'Apheresis method' turns out to be a regular procedure. This is a method of removing a particular constituent of the blood, such as platelets. This process could be also carried out to collect Red Blood Cells (RBC)or plasma or White Blood Cells (WBC). Apheresis donation process takes longer than that for whole blood donation. While an apheresis procedure takes about one to two hours, a normal whole blood donation takes about 1525 minutes.

An adult human has about 46 liters of blood circulating in the body. This is continuously pumping around our body. Every time the heart beats it is pumping more blood to lungs. Blood consists of several types of cells (RBC, WBC and Platelet) floating around in a fluid called plasma. RBC contains haemoglobin that transports oxygen to the body tissues and used to treat anaemia. This can be stored under refrigeration for approximately 6 weeks. The WBC fights infection by killing germs. The platelets help the blood to clot such as in case of a wound -- in general used in patients with dengue, leukaemia and cancer. This can be stored at room temperature unlike RBC and may be kept for a maximum of five days. Plasma holds salts and various kinds of proteins. Fresh frozen plasma, used to control bleeding can be kept in a frozen state for around one year.

The differences in human blood are due to the presence or absence of antigens and antibodies. The antigens are placed on the surface of the red blood cells and the antibodies are to be found in the blood plasma. There are about 20 genetically identified blood groups, but the ABO and Rh systems are the important ones used for blood transfusions. That's why common people are usually aware of four groups in blood. They are O (positive/negative, A (positive/negative, B (positive/negative), and AB(positive/negative). In an emergency, anyone can receive type O (universal donors) and type AB individuals can receive red blood cells of any ABO type (universal recipients). After blood has been drawn, it is usually tested in our centres for ABO group (blood type) and Rh type (positive or negative). In advanced centres it can be also tested for any unexpected red blood cell antibodies that may cause problems in a recipient.

Screening tests can be also performed for evidence of hepatitis B and C viruses, Human Immunodeficiency Viruses (HIV) and Syphilis. Some reputed centres around the world are currently working on artificial blood, with different techniques. Bangladeshi scientists are also involved in these researches -- so we can feel proud that 'Bangladeshis' are doing their bit for the world as well.