About Blood Donations

Blood, vital fluid found in humans and other animals that provides important nourishment to all body organs and tissues and carries away waste materials. Sometimes referred to as “the river of life,” blood is pumped from the heart through a network of blood vessels collectively known as the circulatory system.

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An adult human has about 5 to 6 liters (1 to 2 gal) of blood, which is roughly 7 to 8 percent of total body weight.

bone marrow imageIn fants and children have comparably lower volumes of blood, roughly proportionate to their smaller size. The volume of blood in an individual fluctuates. During dehydration, for example while running a marathon, blood volume decreases. Blood volume increases in circumstances such as pregnancy, when the mother’s blood needs to carry extra oxygen and nutrients to the baby.

Male donors can give blood/donate every 12 weeks. That's approximately every 3 months or 4 times in a 12 month period. Female donors can give every 16 weeks or approximately every 4 months.


Why give blood?

Donated blood is a lifeline for many people needing long-term treatments, not just in emergencies. Your blood's main components: red cells, plasma and platelets are vital for many different uses.

Red cells, plasma and platelets

Red cells are used predominantly in treatment of anemia, in surgeries and major burns. Plasma provides proteins, nutrients and clotting factors that are vital to stop bleeding after trauma - it is the most versatile component of your blood. Platelets are tiny cells used to help patients at a high risk of bleeding as they help in coagulation of blood.

Short shelf-life


Maintaining a regular supply of blood to all the people who need it is not easy. Blood components have a short shelf life. By giving blood, every donor is contributing to a nation-wide challenge to provide life-saving products whenever and wherever they are needed.

Red cells - up to 35 days(2 to 8 centigrade)
Plasma - up to one year(frozen)
Platelets - up to seven days(Room temperature)

Balancing blood types

Ever since a national blood service was first created in 1946, we have relied on the generosity of blood donors not only to maintain stock levels for all our hospitals, but to provide the necessary range of eight blood types. We are indebted to our regular donors for their role in helping us to save lives.

We sometimes need to target specific blood types to increase stock levels. This is particularly true of O Rh negative blood, which is rare but essential because it is the only blood type that can be given to anyone, regardless of their blood type. Donors with the blood group B Rh negative are more often found in black and south Asian minority ethnic communities. Because only 2 per cent of the populations have this blood group, we often appeal for more B- donors.

Who can give blood?

Most people can give blood. As long as you are fit and healthy, weigh over 7 stone 12 lbs (50kg) and are aged between 17 and 66 (up to 70 if you have given blood before) you should be able to give blood. If you are over 70, you need to have given blood in the last two years to continue donating. However, if you are female, aged less than 20 years old and weigh less than 65kg (10st 3lb) and are under 168cm (5' 6") in height, we need to estimate your blood volume before donating.

Who Can't Give Blood?

Although most people are potentially able to give blood, some are not.

There are a variety of reasons why we might ask you not to give blood, but they fall into two main categories. Firstly, if evidence suggests that donating blood could potentially harm you, then to protect your safety we would ask you not to donate. Secondly, if evidence suggests that your donation could potentially harm the patient receiving it, then we would ask you not to donate. 
This would include the situation where a specific behavior may have put you at a higher risk of an infection which could be transmitted to a patient by blood.

Many of the rules implemented in the UK on who can give blood are a requirement of European law. However, there are a number of expert committees that regularly review the evidence relating to exclusions and deferrals from blood donation. Policies which specifically relate to the safety of blood for patients are recommended to the Government by the independent advisory committee on the Safety of Blood, Tissues and Organs (SaBTO). A key part of their work is to ensure that the policies applied by the UK Blood Services are based on the best available scientific evidence.

If you are not able to give blood we know this can be disappointing. However, we hope you will understand that our overriding responsibility is to ensure the safety of donors and the safety of blood for patients.

How to prepare yourself to give Blood

  • Eat regular meals to help you avoid feeling lightheaded.

  • Sleep A good night's sleep will boost wellbeing.

  • Drink plenty of fluids 24 hours before donating, but avoid alcohol

  • Wear Put on loose and comfortable clothing, avoid tight sleeves

  • Distract Nervousness is normal, come with a friend or bring along a book or MP3 player so you can relax during your visit.

  • Know Knowing your medical, body piercing and travel history will save you time.

  • Keep well hydrated Keep well hydrated always important for donating blood, and while we do urgently want donors, please don't rush and wear cool loose clothing. It's better if you can be cool and relaxed for your donation

Component Donation

Component donation is a specialized way of donating using a cell separator machine. These machines separate the blood into all its various components: platelets, red cells, plasma & white cells. We take out just what we need and put back into your body what we don't. Because the large majority of blood components are returned, the donor can safely donate more frequently than every 16 weeks. In some cases, this can be every two weeks.

A component donation is very important as this allows us to collect individual parts of the blood as and when we need them most. If there is a need for we can quickly ask platelet donors to come into one of our blood donation suites to donate. There we can collect platelets to meet the required demand. In fact, sometimes a donor will donate for a specific patient's planned treatment.

Welcome and Preparation

Before donating blood, please eat regular meals, drink plenty of fluid (non-alcoholic) and avoid vigorous exercise or exertion. When you attend your donation session please read our Welcome leaflet provided. This explains the importance of Blood Safety. It’s important to read this whenever you attend because advice does change. We must give you sufficient information so that you can make an informed choice, on the benefits and risks of donating blood and samples for testing. We will provide 500ml of fluid just before you donate. By drinking this over about five minutes, it will help with your wellbeing during and after donation.

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