Donate blood – the procedures and reasons why

This is according to South African National Blood Service (SANBS) Limpopo public relations officer, Dottie Pinn. “The antigens are located on the surface of the red blood cells and the antibodies are in the blood plasma. Individuals have different types and combinations of these molecules. The blood group you belong to depends on what you have inherited from your parents,” she explained.

Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals, she further explained.

“Many people also have the Rh factor on their red blood cell’s surface. This is also an antigen and those who have it are called Rh+. Those who haven’t are called Rh-. A person with Rh- blood does not have Rh antibodies naturally in the blood plasma. But a person with Rh- blood can develop Rh antibodies in the blood plasma if he or she receives blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies. A person with Rh+ blood can receive blood from a person with Rh-blood without any problems.”

According to the AB0 blood typing system there are four different kinds of blood types namely A, B, AB or O.

“If you belong to group A blood, you have A antigens on the surface of your red blood cells and B antibodies in your blood plasma,” Pinn explained.

If you belong to the blood group B, you have B antigens on the surface of your red blood cells and A antibodies in your blood plasma, she continued.

“If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and no A or B antibodies at all in your blood plasma.

“People with AB positive blood types are the “universal recipients” as they can receive blood from all blood groups.”

If you belong to the blood group O, you have neither A or B antigens on the surface of your red blood cells, but you have both A and B antibodies in your blood plasma.

O negative blood can be given to anyone in an emergency and O negative donors are known as the “universal donors”.

“Blood is vital to human life. It carries essential nourishment to all the tissue and organs of the body. Without it, the tissues will die. The average person has 25 billion red blood cells and, in a normal healthy person, cells are constantly regenerated in the body. Without the protection of blood, no child could be born,” Pinn said.

In the womb, the mother’s blood ensures that the foetus is supplied with oxygen and nutrients and benefits from the mother’s inbuilt defences against disease.

About 45% of the total volume of blood is made up of red blood cells, white blood cells and platelets.

“Red blood cells carry oxygen. The haemoglobin, which gives blood its red colour, is the agent that needs to be present for oxygen to be taken up from the lungs. Red blood cells also transport carbon dioxide back to the lungs, for expulsion from the body. Iron is the key factor in the manufacture of haemoglobin. When iron supplies are deficient, people become anaemic, with a corresponding loss of oxygen-carrying ability.”

White blood cells defend the body against disease. They make antibodies and fight infections.

Platelets help to control bleeding by sticking to the injured surfaces of blood vessels, and allowing clotting factors to accumulate at the injury site. Plasma is a fluid which carries all these cells, plus other substances such as proteins, clotting factors and chemicals.

Sometimes, through trauma such as a haemorrhage, the volume of blood in the body is reduced to such a level that the body cannot replace it fast enough.

Occasionally, some components of the blood are lacking and do not function correctly, as is the case with haemophilia, where clotting of the blood does not occur. At other times, the bone marrow does not produce sufficient haemoglobin, due to a deficiency of the necessary building blocks.

“In most cases, blood and blood components will be transfused to patients. All the different components of blood can be used and each plays an important role in saving the lives of different individuals in the community,” Pinn explained.

Blood has four main components namely red blood cells, white blood cells, plasma and platelets all of which are used by patients in need.

One unit of blood can be separated into the different components a unit of blood can save up to three lives as blood is separated into red blood cells, plasma and platelets.

“The average healthy person can donate blood 330 times in their life. The rarest blood type is AB negative where less than 1% of the population have that. Human blood is 78% water,” she said.

Pinn added that donating a unit of this “precious gift of life” saved the lives of those in dire need of blood. “One must develop a habit of donating blood in order for the SANBS to collect sufficient blood that will ensure that in cases of emergency quality blood is always available for needy patients.

“Safe blood saves lives. Thousands of patients would die daily if there is insufficient quality blood in stock. When one donates blood, they give patients the gift money cannot buy or science cannot create.”

There are different categories of people needing blood transfusion:

• Women haemorrhaging due to pregnancy complication and other gynaecological complications.
• Children with severe anaemia.
• Accident victims.
• Surgical and cancer patients.

“You make a difference in somebody’s life by donating blood,” Pinn said.

She explained that there was a donation procedure during which a prospective donor would complete a questionnaire containing personal details, answer questions relating to his or her health and social behaviour and lifestyle, participate in a one-on-one interview as a follow-up to the answers, have his or her iron (haemoglobin) level checked, and blood pressure and pulse rate taken.

They will then be allowed to donate one unit of blood (480ml).

“Donating blood is a safe and simple procedure that takes about 30 minutes. All needles are new, sterile, used only once and incinerated after use,” Pinn concluded.