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Blood donation


Why do we need blood donations?

Blood donations are an integral and essential  part of our health care system and without them many of the medical procedures that we take for granted could not take place. Doctors and surgeons rely on blood donations to carry out a wide variety of life saving and life enhancing treatments on a daily basis.

Only  4% of the eligible population currently donate blood, but the need for blood transfusions remains consistently high. Anything up to three million donations a year are needed in the UK alone to keep pace with all the treatments that are carried out.

As blood can only be safely stored for a relatively short time, hospital blood stocks need to be continuously refreshed. For example, red blood cells can only be stored for 35 days and platelets (the part of the blood that helps prevent excessive bleeding) can only be stored for five days.

In particular, blood donations are needed from black and Asian people because the current levels of black and Asian donors are very low. Certain ethnic groups often require certain blood types, so having a range of donations from a wide range of ethnic groups is a more effective way to meet the potential demand for blood.

In North Wales the blood donation process is overseen by the National Blood Service, in South, Mid and West Wales by the Welsh Blood Service. The Blood Service relies on voluntary donations tfrom the general public to keep the service running. Donating blood is a relatively quick procedure (it usually takes less than an hour) and is virtually painless.

The website of the Welsh Blood Service provides more information about how you can volunteer to give blood.

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How is it performed?

Blood donor sessions take place all over the country throughout the year. Many donor units are mobile and there are often donor centres within large cities. Telephone the Welsh Blood Service on 0800 252 266 or National Blood Service on 0300 123 2323 if you are living in North Wales to make an appointment at your local centre, or visit their website for details at or

Before donating blood

Before you donate blood, you should make sure that you eat and drink at least a few hours before you are due to donate. This will help stop you from feeling faint, or dizzy, after the procedure. Do not drink alcohol before giving blood.

When you arrive

When you arrive to donate blood, you will first be given a series of information leaflets to read. It is very important that you read this information because it will help to ensure that you are suitable to give blood, and will also explain the procedure.

You will then need to fill in a confidential donor health check form. You will be asked to answer a number of questions about your health and lifestyle. It is very important that you answer the questions honestly and accurately, in order to ensure that the blood you donate is safe to use (see the 'who can use it' section).

People who are donating blood for the first time may also need to have a confidential discussion with a nurse, to help ensure they will be suitable for blood donation.

Anaemia check

Once you have completed your donor health check form, a very small sample of blood will be taken from your finger tip. Only a droplet of blood is needed. This blood is tested to see how much haemoglobin it contains.

Haemoglobin is a substance that is present in red blood cells. It helps carry oxygen around the body. Anaemia is a condition which occurs when you do not have enough red blood cells, or when the cells you do have, do not contain enough haemoglobin. Symptoms of anaemia can include:

  • tiredness,
  • lethargy,
  • shortness of breath, and
  • palpitaions (irregular heart beat).

If your haemoglobin level is very low, it may mean that giving blood could make you anaemic. If this is the case, you may have to be referred to your GP before you can give blood.

Donating blood

Once you have passed all of the necessary health checks, you will be able to donate blood. It usually takes between 10-15 minutes for a sample of your blood to be collected.

A cuff will usually be placed around your arm. The cuff is inflated to help make it easier for the health professional to access the veins in your arm.

A sterile needle is inserted into a vein and held in place with tape. You will barely feel the needle. Once the needle is in place, a syringe will be used to collect a sample of your blood. The needle is only used once and it is discarded after your donation.

During most blood donations, approximately 470ml of blood is taken. This is just under one pint, and only makes up 10-12% of an adult's blood supply. Your body is able to make up this amount of lost blood very quickly. If you are well hydrated following your donation, your body will make up the fluid part of the blood within a few hours. It takes just a few weeks for your body to replace the lost blood cells.

After donating

After you donate blood, you will need to rest for a short while. You will be offered refreshments to help stop you from feeling faint, or dizzy. The whole process of donating blood should not take longer than an hour.

If you become unwell within two weeks of your donation, you should call the National Blood Service on 0300 123 2323 for North Wales or Welsh Blood Service on 0800 252 266 for South, Mid and West Wales. You should also call these numbers if you feel persistently faint following your donation. If you are concerned about your symptoms, you can also call NHS Direct Wales on 0845 46 47 for further advice.

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What is it used for?

Blood donations save lives every day. They are used in a wide variety of different situations, and to treat a large number of different illnesses and conditions.

Different components

After your blood has been collected for donation, it is sent for testing in a laboratory. Here it is screened for various viruses and infections, such as HIV and hepatitis. If the blood passes this screening, it will usually be separated into different components. In this way, your blood donation can be used to help several different patients. Once the blood has been separated, it is distributed to hospitals all over the country.

The different components blood donations are split into are outlined below.

Whole blood

If someone receives whole blood, it means the blood has not been separated into its different components. However, whole blood is rarely used any more, and it is only useful in cases of severe blood loss.

Red blood cells

Red blood cells are the cells which carry oxygen around the body in a substance known as haemoglobin.

Red blood cells are often used to treat types of anaemia which do not always respond to other forms of treatment, such as medication. For example, sickle cell anaemia (a genetic condition which stops the red cells from carrying enough oxygen) is sometimes treated using red cells.

Red blood cells are often also used to replace blood which is lost as a result of an accident, surgery, or during childbirth. In some cases, these cells are also used prior to operations and surgical procedures. For example, you may need pre-operative red blood cells if you are severely anaemic, or have severe burns.


Platelets are the cells in your blood which help it to clot. They are often used to treat bone marrow failure. Bone marrow is the spongy tissue inside your bones that helps to produce new blood cells. When the bone marrow is not able to produce enough cells, it is known as bone marrow failure.

Platelets are also used to treat leukaemia (a form of cancer which affects the blood cells).


Plasma is a yellow coloured fluid which helps to carry all of the different types of blood cells. Plasma can either be frozen or processed.

Frozen plasma is used to help replace blood which is lost during childbirth, or cardiac (heart) surgery. It can also be used to reverse anti-coagulant treatment by encouraging the blood to clot.

Processed plasma is used to treat haemophilia (a condition which stops your blood from clotting normally). It is also used to help produce a substance known as anti-D. This substance helps prevent a condition known as rhesus disease, which occurs when antibodies in a mother's blood attack her baby's blood cells.

Terminal illness

As well as saving lives, blood donations can also help to improve the quality of life of people with a terminal illness. A blood transfusion may be able to give them the energy to spend time with their friends and relatives that they might not have otherwise had.

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Who can use it?

Most people who are between 17-66 years of age, weigh over 50kg (7st 12lb), and have good general health, will be able to donate blood.

You can donate blood every 16 weeks (roughly every 4 months), and regular donors can donate up until they are 70 years of age.

Who cannot donate blood?

Before you donate blood, you will be asked to fill out a confidential donor health check form (see the 'how it is performed' section). You will need to fill out this form to check that your blood will be suitable for donation.

Unfortunately, not everyone can donate blood. This is to ensure that those people receiving the blood are not exposed to any harmful viruses, or infections.

You may not be able to donate blood if:

  • you have had a serious illness, or major surgery in the past,
  • you are currently taking certain types of medication, such as those used to prevent blood clotting (you usually have to stop taking these medications for at least seven days before making a donation)
  • you have had complicated dental work (it is safe to donate blood 24 hours after a filling, or seven days after a simple extraction),
  • you have recently come into contact with an infectious disease,
  • you have had certain immunisations within the last four weeks, or
  • you are currently on a hospital waiting list, or you are waiting to undergo tests.

If any of these apply to you, you can call the National Blood Service (0300 123 2323) for North Wales, and the Welsh Blood Service (0800 252 266) for South, Mid and West Wales who will be able to give you more specific advice about whether or not you are suitable for blood donation. For example, not all types of medication, or immunisations, will mean that you cannot give blood.

You should not give blood if:

  • you have a chesty cough, sore throat, or active cold sore,
  • you are taking antibiotics, or have finished a course of antibiotics with the last seven days,
  • you have had hepatitis A, or jaundice, in the last 12 months,
  • you have had ear, or body piercing, in the last six months,
  • you have had a tattoo in the last six months,
  • a member of your immediate family has had Creutzfeldt-Jakob disease (CJD) which is a rare condition that affects the nervous system and causes brain damage.
  • you have had acupuncture outside of the NHS,
  • you have received human pituitary extract (a substance that was used in some growth hormone and fertility treatments before 1985), or
  • you have ever received blood during the course of a medical treatment, or procedure, since 1980.

You should never donate blood if:

  • you have HIV,
  • you have hepatitis B or C,
  • you are a man who has had sex with another man, even with a condom (see below)
  • you have ever injected yourself with drugs, or
  • you have ever worked as a prostitute.

You should not donate blood for 12 months after having sex with:

  • a prostitute,
  • a man who has had oral or anal sex with another man (if you are female),
  • someone who has injected drugs,
  • someone who has haemophilia (a condition which stops your blood from clotting normally), or
  • someone who has been sexually active in parts of the world where AIDS and HIV is common, such as sub-Sarahan Africa.

Gay men and blood donation

The National Blood Service has a duty of care to minimise the risk of a blood transfusion transmitting an infection, such as HIV or hepatitis C, to a person receiving a donation.

All donated blood is rigorously tested. However, there is always a small chance of mistakes being made, such as the accidental transmission of infections.

The National Blood Service works on the principle that any transmission of infection is one too many, and it does everything it possibly can to minimise this risk. Therefore, the organisation has a long-standing policy of not accepting blood donations from groups that have been shown to have a particularly high risk of carrying blood-borne infections, such as sexually active gay men (men who have had anal or oral sex at least once with another man).

It should be emphasised that this decision is based on specific sexual behaviour (namely anal and oral sex between men), not sexuality. Blood donations are accepted from gay men who have never had sex with a man, and women who have sex with other women.

The medical reasons behind the policy for not accepting blood donations from some gay men are listed below:

  • While condoms can reduce the risk of transmission of infections, they cannot eliminate the risk altogether. Sexually active gay men are disproportionately affected by HIV (accounting for 63% of diagnosed cases in the UK) as well as other blood-borne infections, such as hepatitis B and syphilis.
  • While all donations are tested for the presence of infectious agents, such as HIV, there is a small ‘window of opportunity’ between a person catching an infection and the infection showing up on a test, so a small number of infected donations may be missed.
  • Research shows that if this policy was withdrawn, there would be a five-fold increase in the risk of HIV-infected blood entering the blood supply.

The Terrence Higgins Trust is a leading sexual health charity that has a particular focus on issues that affect gay people. It supports this policy and has asked that gay men abide by it.

The policy is regularly reviewed taking into account the latest evidence, with the next planned review expected to take place some time during 2010.

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