(b) Red Cells: carry oxygen from lungs to various body tissues and take back carbon dioxide from the cells and tissues to be thrown out of body in the form of exhaled air.

(c) White cells: are mainly acting as body scavengers and guards. They help in the immune system of the body and act as defense forces of the body killing the bacteria or any other organisms enter in the body.

(d) Platelets: help in the clotting and coagulation of blood. We have experienced in our life that whenever we get injured the bleeding stops after a few minutes. This brought about by a mechanism called clotting of blood in which platelet plays a very vital role.

Red blood cells have life of 120 days - which means any red cell formed in the body will live for the next 120 days and when it becomes old and senile it is thrown out. White cells for few days and platelets for a few hours. Thus daily new cells are added to the circulation and old is removed from it.

In the ABO - Group there are four categories namely "A" Group, "B" Group, "O" Group and "AB" Group.

In the Rh - Group either the individual is Rh-positive, or Rh-negative. Rh- is a factor called as Rhesus factor that has come to us from our ancestors called Rhesus monkeys.

Thus each and very human being will fall in one of the following Groups. A positive or A negative
B positive or B negative
O positive or O negative
AB positive or AB negative
Although there are certain sub groups also besides some other classifications. For all practical purposes this should suffice.

In the females who have Rh negative with their husbands being Rh positive, the first child with Rh positive may be normal, subsequently she may not conceive or may have repeated abortions. There may be intra uterine fetal death. If the child born is alive, it will suffer from a fatal disease called "Erythroblastosis Foetalis.” Now mother's can be given an injection of anti-D within 24 hours of the delivery of a Rh-positive child and thus protect the next baby from this catastrophe.

No major surgery is performed without blood as there is bound to be blood loss. On an average, for every open heart surgery about 6 units of blood is required per head. In Gynecological and Obstetrics departments a lady may need large amount of blood to be transfused for saving not only her life but also of the child that she carries in situations APH (bleeding before birth), or PPH (bleeding after birth).

For patients with blood diseases like severe Anaemias especially Aplastic Anaemias Leucaemias (blood cancer) Haemophilia (bleeding disorder), Thalassemia etc. Blood is the only hope for, living and they have to get repeated transfusions. In many cases like poisoning, drug reactions, and conditions of shock, burns and many other situations, blood transfusion is the only way to save the precious human life.

To put it in a nutshell, "There is no SUBSTITUTE FOR BLOOD and a patient who needs blood to save his life can only be saved if blood is transfused to him".

(1) PROFESSIONAL DONORS - who sell their blood for money. Actually these are slurs and curse on our civilized society. Under no circumstances professional donors should be allowed to give blood. They sell their blood, which is of very poor quality and can transmit very dangerous diseases to the recipient. It is illegal to take blood from any professional donor.

(2) REPLACEMENT DONATION- the healthy relatives and friends of the patient give their blood of any groups in the blood bank. However from the stocks available in the blood bank, the required number of units of the same blood group as that of the patient is given. This is called as Replacement Donations.

(3) VOLUNTARY DONATION- Here a donor donates his blood voluntarily. His blood can be used for any patient even without telling his identity. This is the BEST TYPE of blood donation where motivated human being give their blood in an act of high human selfless service--NISHKAMA SEVA.

Jaundice: A donor must not have his blood-tested positive for AUSTRALIA ANTIGEN.

Blood transmitted diseases: Like Syphilis, Malaria, Filaria etc., debar a donor from donating blood till he is treated and is free from them.

Drug: If a donor is taking drugs like Aspirin, anti-hypertensive, anti-diabetics, hormones, corticosteroids etc., he is unfit to donate blood. AIDS. No person having HIV positive can be allowed to donate blood.

Transfusion Reactions

1. Febrile (Fever) or Pyrogenic reactions with in 1 to 24 hours.
2. Allergic reactions.
3. Haemolytic reactions-this is severe and some times fatal (death).
4. Transmission of diseases-syphilis, jaundice, malaria, AIDS etc.
5. Cardiac over load.
6. Electrolytic reactions. e.g.:
Too much citrate leads to calcium depletion which results in tetany , bleeding etc., Potassium intoxication - Hyper Kalemia.
7. Hemorrhagic reactions due to massive transfusion.
8. Transfusion Siderosis (Iron excess)
9. Thrombophlebitis
10. Iso- sensitization.
11. Rarely - Air and fat embolisms

TRANSFUSION WITH INCOMPATIBLE BLOOD {MISMATCHED BLOOD}

The symptoms begin only after a few ml. of blood has been given:

1. Patient complains of shivering, restlessness, nausea, and vomiting. Precardial and lumbar pain.

2. Cold, clammy skin with cyanosis.

3. Pulse rate increases, respiratory rate increases. Temperature increases to 38? to 40? C. [101 to 105 F].

4. B. P. falls and patient passes into a state of shock.

5. Haemoglobinaemia, haemoglobinurea (urine turns red); Oliguria (urine becomes scanty or the urinary output is reduced) and Anuria (total output of urine becomes 200 ml. a day)

6. Jaundice appears after a few hours and in some cases anuria persists and uremia develops. This may lead to death.

Truly speaking these days in good blood banks more than 85 % blood collected is converted into components and stored. The patients may not require whole blood for example a patient whose hemoglobin is low and is thus anemic may just require Packed Cells i.e. only red cells or a patient with burns may need more of plasma than cells; or a patient with hemophilia may just require factor VIII.

Thus component therapy has revolutionized the blood transfusion services all over the world.

Now with the advent of Cell- separators we can draw a particular component from the donor directly and rest of the constituents go back to the donor. Such a facility exists in a few of the blood banks in our country.