An adult male or female carries about 5 litres of blood in the blood circulation system. This volume is less in children by about a litre (- 0.8 litres).
During blood donation, what is removed is less than 10% of the total blood volume. About 500 ml of blood is removed from the donor’s vein, within 24 hours of blood donation, this volume is replaced. The donor is usually advised to increase his fluid intake. Although haemoglobin concentration falls following a blood donation, but within 2 months, haemoglobin returns to its previous value (pre-donation status) even without taking drugs. In some centres, milk or stout or fergon tablets are prescribed for the donor. They stimulate the bone marrow to produce more blood in order to improve the haemoglobin concentration. Good food containing protein (eggs, milk etc) vitamins and minerals (fruits and vegetables) help to stimulate the marrow to produce blood. A healthy individual can donate blood every three months, if he maintains good nutritional status.
The age group allowed for blood donation is 16 to 65 years in developed countries such as Europe, America, USSR; and 18 -60 years in developing countries (Nigeria). The difference in age group lies in the nutritional state of communities in developing countries, where feeding is not as good as that in developed countries. Women and men can donate equal volume of blood. Menstruation is not a risk factor. Pregnancy and childbirth are risk factors. Blood volume varies with age as it has already been mentioned. The blood volume in a child is not the same as that in an adult. Differences have been found in blood volume of individuals within the same age group and their weights. A positive relationship exists between body size and blood volume of children although the difference is not much.
As a rule any adult who is in good health and has not had any serious illness is a suitable donor of blood. There are regulations designed to protect the donor and the recipient. A blood donor may be disqualified from donating blood if he has the following conditions:-
1. Communicable diseases such as hepatitis, malaria, HIV/ AIDS, syphilis, bacterial infections, trypanosomiasis and few others.
2. Recent injections of vaccines. A donor who has recently been vaccinated should not donate blood because the blood may contain living virus. Donation of blood should be at least one mouth from the day of vaccination.
3. Donors who suffer from severe allergy may transfer their sensitivity to the recipient although for a short period. Hence they should not donate.
4. Presence of inherited red cell abnormality such as sickle cell disease, thalassaemia, G-6-PD deficiency.
5. In pregnancy state, blood donation can cause iron deficiency anaemia.
6. Children are not allowed to donate blood.
7. If the donor has been bled twice before within a year.
8. Anaemia. It is advisable to perform a test on all blood donors to make sure that they are not anaemic. This is achieved by taking a drop of blood from the donor and allowing it to fall into a solution of copper sulphate to determine its specific gravity. The drop either sinks or floats. Donors who are confirmed anaemic should not donate blood.
10. Kidney diseases
11. Old age
12. Blood diseases such as leukaemia.
Healthy males and females can donate a pint of blood once or twice yearly without any side effects,
provided such donors eat well. When the interval between donations is shorter than six months the
donor faces the risk of anaemia. Every donor must be screened and certified fit for blood donation in
order to promote his health and to protect the recipient from acquiring illness following blood transfusion. A healthy person donates blood to a recipient. The purpose of blood donation is blood transfusion.
Certain diseases can be transmitted from person to person through blood transfusion.
(a) Hepatitis A can be transmitted through blood transfusion but rarely. Hepatitis B otherwise known as serum hepatitis can spread through blood transfusion if the transfused blood was obtained from an infected donor. Even laboratory staff handling human blood should take precautions in order not to get infected with blood from infected donors. Some recipients may fall ill after transfusion of infected blood. Others may remain asymptomatic but they are carriers.
(b) HIV/AIDS infection can spread from person to person through blood transfusion, although there are other modes of transmission such as sexual intercourse, use of infected needles and so on.
(c) Malaria can also be transmitted by blood transfusion. Many other parasites such as those causing trypanosomiasis (sleeping sickness), toxoplasmosis and filariasis can be transmitted during blood transfusion.
Blood compatibility is another risk factor in blood transfusion. If by mistake incompatible blood is
transfused, a serious reaction follows which may terminate in death.
Adverse reactions which could occur during blood transfusion include fever, shivering without fever, and skin rashes (allergy). Most of these reactions have to do with the immune system of the recipient.
Blood transfusions are useful in medical practice. Members of the community should donate generously to the blood banks from time to time for use in emergencies. It is common practice to find relations refusing to donate for patient in need. This attitude should be condemned. With adequate precautions, the risk of blood donation can be got rid of.