Blood donation: say it with blood

Our body has more blood than it needs—maybe to enable us to share it with those unfortunate people, lying on the deathbed, fighting for their lives. Blood donation gives us this opportunity.A person, weighing over 50kg, has 5 – 6 litres of blood in his body, depending on his weight and muscular build. He has an extra 500ml blood, which is stored in the spleen and liver. Out of this extra 500ml, we donate 350ml or 450ml.

All blood in the body—the circulating as well as the stored—lasts 120 days. After that, our body destroys it. Every day, our body destroys about one per cent of the stored blood; while one per cent is formed in the bones. This stored extra blood, which is destroyed anyway, is what we donate.

Blood breakup

Blood is made of several components: red blood cells [RBCs], white blood cells [WBCs], platelets and plasma. The RBCs have haemoglobin and carry oxygen. They give us strength, stamina and power. The WBCs are our defence system against bacteria, viruses and other pathogens and foreign tissue. The platelets are sealants to the blood vessels. The plasma is a mixture of highly complex protein molecules that are diverse in structure and serve diverse functions.

The RBCs have complex molecules on their surface called antigens. Based on the type of antigen that an individual’s RBC possesses, the person is said to be of a particular blood group. There are four major groups A, B, O and AB. Each group has two more types, Rh-positive and Rh-negative.

Our blood group often decides who we can / cannot donate blood to.

• Those in the AB group can give blood to AB and receive from A, B, AB, O.
• Those in the A group can give blood to A and AB and receive from those in A and O.
• Those in the B group can give blood to B and AB and receive from B and O.
• Those with a O group can give blood to A, B, AB, O and receive only from individuals from O.

Note: O-ve people should receive blood only from O-ve people. Those with Rh +ve can receive blood from both –ve and +ve. People with blood group O Rh-ve are called ‘universal donors’ and people with blood group AB Rh+ve are called ‘universal receivers’.

Step-by-step

Blood donation involves a very simple procedure.

Step-1: Your preliminary details and consent are taken. A weight check and a medical exam are done to evaluate if you are fit to donate blood. Your medical history is then taken to rule out any past illness that can make you unfit for donating blood. Your haemoglobin is tested using the finger-prick method with a sterile needle. If you are found fit for donation, you proceed.

Step-2: You are asked to lie down after drinking two glasses of water.

Step-3: A blood-pressure instrument is tied to your arm, and your forearm is cleaned with spirit to make it germ-free.

Step-4: Blood is then collected via a sterile needle inserted in the vein. It takes 4 – 7 minutes to collect 350 ml blood.

Step-5: After the blood is collected, the needle is removed and your arm is folded with tight pressure. You are to remain lying down and not straighten your arm for at least three minutes. Then, a bandage is applied, which you have to press for five more minutes.

Step-6: You are then given a glass of water, tea/coffee and biscuits and kept under observation.

All of this takes 15 – 20 minutes.

Who needs blood?

The blood you donate goes to blood banks. Many blood banks process the blood to separate: packed red blood cells, platelets, fresh frozen plasma and cryoprecipitate. These components are then given to individuals who need this blood—patients of accidents, operations, childbirth, cancer, kidney diseases, liver diseases and other serious illnesses. Blood is a complex fluid that it cannot be manufactured in a factory. Blood has no substitute, except human blood.

Who can donate blood?

Anyone who has completed 18 years of age and is below 60 years can donate blood, if s/he weighs more than 45 kg and is in good health, mentally alert and physically fit. S/he should not be having multiple sex partners and should not be a drug addict. The donor should have haemoglobin of more than 12.5g per cent, normal blood pressure and should be free from any illness for 10 days prior to donating blood.

Who cannot donate blood?

Individuals suffering from cancer, heart disease, abnormal bleeding tendencies, unexplained weight loss, frequent fever, loose motion, cough, diabetes that needs insulin, hepatitis-B infection, HIV affected, kidney disease, liver disease, tuberculosis, asthma, epilepsy, leprosy, schizophrenia and endocrine disorders cannot donate blood.

After immunisation with cholera, typhoid, diphtheria, tetanus, plague or a gammaglobulin injection, a person cannot donate blood for 15 days. After a bout of malarial fever, an individual cannot donate for three months. After an abortion, blood transfusion or a tattoo, an individual cannot donate for six months. After an operation, typhoid fever, delivery, hepatitis in family or immunoglobulin injection, an individual cannot donate for one year.

How frequently can one donate blood?

You can donate blood every three months. For aphaeresis [Aphaeresis is a special blood donation process in which an individual donates blood in a machine called cell separator for 6 – 7 minutes], you can donate twice a week and a maximum of 24 times a year, if no whole blood donation is done in between.