Blood donation
Blood donation

Blood donation involves collecting blood from a donor so it can be used to treat someone else.

Blood donations are an essential part of our healthcare system. If we did not have volunteers giving blood, many medical procedures we take for granted could not take place.

Doctors and surgeons rely on blood donations to carry out life-saving and life-enhancing treatments every day.

How can I donate blood?

In South, Mid and West Wales by the Welsh Blood Service, in North Wales the blood donation process is overseen by the National Blood Service . Both Blood Services rely on voluntary donations from 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  Welsh Blood Service provides more information about how you can volunteer to give blood.

Thousands of blood donation sessions are held each year by the Welsh blood service and NHS Blood and Transplant, so it is usually possible to attend one convenient for you.

You will need to answer some questions about your health and have a quick blood test before you can donate blood. This is done to ensure there is no danger to yourself or someone else.

It is recommended that you drink at least 500ml of water immediately prior to donating, and again once the donation is finished.

During a blood donation, a needle is used to collect 470ml (just under one pint) of your blood.

You will need to rest for a short while after a donation and refreshments will be offered to stop you feeling faint or dizzy.

It is usually recommended that men allow 12 weeks and women 16 weeks between donations.

Read more about how blood donations are performed.

How is donated blood used?

In most cases, your blood will be separated into its component parts so it can be used to treat a variety of conditions. These components are:

  • red blood cells  used to treat some types of anaemia and replace blood lost as the result of an accident
  • platelets  used to treat problems with bone marrow, such as leukaemia and people with blood clotting disorders
  • plasma  used to treat conditions where abnormal clotting causes bleeding, such as liver disease, and where large volumes of blood have been lost

Donated blood may also be used to improve the life of someone with a terminal illness.

Read more about how blood donations are used.

Other types of blood donation

As well as normal blood donation, there are other types of donation that can be used to treat other conditions, such as cord blood or platelet donation.

Cord blood donation

Cord blood  from the placenta and umbilical cord can be donated after a baby has been born. However, a decision must be made before the birth.

Cord blood, which is rich in stem cells, can be used to treat a number of conditions, such as leukaemia.

Read more about cord blood donation.

Platelet donation

If you have a high platelet count in your blood, you may be able to directly donate platelets. The process is similar to giving blood normally, but often takes a bit longer.

Read more about platelet donation.

Who can donate blood?

Most people between the ages of 17 and 65 can donate blood, although you must be in good general health.

To reduce the risk to recipients of donated blood, there are rules about who can and cannot donate blood.

For example, people who have HIV, or have ever had syphilis or hepatitis C can never donate blood.

However, some more common things, such as having a recent piercing or taking certain medication, may also mean you cannot donate blood.

Read more about who can donate blood.

More blood donors are needed

Although most people are able to give blood, only about 4% of the population donate regularly. Therefore, the need for blood donations remains high.

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 seven 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 of meeting the potential demand for blood.

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How is it performed?

In most cases, blood donation is a relatively straightforward process.

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 www.welsh-blood.org.uk or www.blood.co.uk.

It is recommended that men only donate blood every 12 weeks and women only donate every 16 weeks (four months). The minimum period between donations is 12 weeks, unless you have a condition called haemachromatosis, in which case a shorter interval may be allowed.

Before donating blood

Before you donate blood, you should make sure that you eat and drink at least a few hours before your appointment. This will help stop you from feeling faint, or dizzy, after you have given blood. Do not drink alcohol before you give blood.

Suitability checks

When you arrive at the donation centre to donate blood, you will be given some information to read. It is important you read this information because it will explain the procedure and help ensure you are suitable to give blood.

After reading the information, you will be asked to fill in a confidential donor health check form. You will be asked a number of questions about your health and lifestyle. It is very important you answer the questions honestly and accurately to ensure the blood you donate is safe to use.

If you are donating blood for the first time, you may also have a confidential discussion with a nurse.

Read more about who can give blood donations.

Anaemia check

Once you have completed your donor health check form, a droplet of blood will be taken from your finger tip to check how much haemoglobin it contains.

Haemoglobin is a substance present in red blood cells. It helps carry oxygen around the body. Anaemia is a condition that occurs when you do not have enough red blood cells or when the blood cells do not contain enough haemoglobin. The most common type of anaemia is sometimes known as iron deficiency anaemia.

Symptoms of anaemia can include:

  • tiredness
  • lethargy
  • shortness of breath
  • palpitations (irregular heartbeat)

If your haemoglobin level is very low, giving blood could make you anaemic. If this is the case, you may need to visit your GP before you can give blood.

Read more about iron deficiency anaemia.

Donating blood

Once you have passed all necessary health checks, you will be able to donate blood. It usually takes 10 to 15 minutes for your blood donation to be collected.

The donation procedure will usually involve a cuff being placed around your arm. The cuff will be inflated to help make it easier for the healthcare professional to access the veins in your arm.

Your arm will be cleaned and a sterile needle inserted into a vein in your arm that is held in place with tape.

You will barely feel the needle. The needle will be used only once and will be discarded after your donation.

During most blood donations, approximately 470ml (just under one pint) of blood will be taken. This amount is only around 10% of an adult's blood supply and your body will be able to replace it very quickly.

As long as you are well hydrated after your blood donation, your body will make up the fluid part of the blood within a few hours. It will take just a few weeks for your body to fully replace all of the blood cells.

Virtual donation session 

You can find out what happens at a blood donor session using the virtual session provided by NHS Blood and Transplant. This takes you through a blood donor session step by step.

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.

You will usually be advised to keep the pressure bandage on your arm for about 30 minutes and the plaster dressing on for six hours.

If you smoke, it is recommended you avoid smoking for two hours after giving blood because smoking could make you feel faint and dizzy.

Donating blood is very safe, although you may experience some mild after effects, such as:

  • bruising at the site where the blood was taken (which affects around one in four people)
  • a sore arm (which affects around one in 10 people)
  • dizziness and fainting (which affects around one in 15 people)

More serious after effects that require medical treatment are rare, occurring in less than one in every 3,500 cases.

To avoid bruising it is recommended that you apply pressure to the place where the needle was inserted until the bleeding has stopped. The dressing that is applied to keep it clean should be kept on for at least 6 hours, You should also avoid heavy lifting as this can aggrevate any pain causd by the bruise. However, gentle movement may be beneficial as can applying something  cool to the area, eg a cold cloth or flannel.

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. Call these numbers if you feel persistently faint following your donation and also if you have numbness, pins and needles  in the arm hands or fingers or swelling or redness of the arm. If you are concerned about your symptoms, you can also call NHS 111 Wales (if available in your area) or 0845 46 47 for further advice.

Blood types

Someone who has a blood transfusion must receive blood from a donor with the same blood type, otherwise their immune system (the body's natural defence against infection) may attack the donated blood. This could lead to potentially life-threatening conditions.

There are two main systems for classifying blood groups. These are:

  • the ABO blood group system
  • the Rh system

Your blood group is determined by your ABO group and your RhD group.

There are also many other groups that are less important for most people, but may be very important for some. If you have one of these rare groups, you may be contacted about making special donations.

Read more about blood types.

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Who can donate?

Most people between the ages of 17 and 66 who weigh over 50kg (7st 12lb) and have a good level of general health will be able to donate blood.

If you are over 70, you need to have given blood in the last two years to continue donating.

Your blood volume may need to be estimated first if you are a women and you:

  • are under 20 years old
  • weigh under 65kg (10st 3lb)
  • are under 168cm (5' 6") in height

It is usually recommended that women leave 16 weeks (4 months) and men 12 weeks (3 months) between donations.

People who cannot donate blood

Before donating blood, you will be asked to fill out a confidential donor health check form. You need to fill out this form to make sure your blood is suitable for donation.

Not everyone can donate blood. The donor health check form is used to ensure that those people receiving the blood are not exposed to any harmful viruses or infections. It's also to avoid putting you at risk if there's a reason why giving blood might harm you.

You may not be able to donate blood if:

  • you have had a serious illness or major surgery in the past
  • you have had complicated dental work (it is safe to donate blood 24 hours after having 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
  • you are currently on a hospital waiting list, or waiting to have tests

If any of these apply to you and you live in South, Mid and West Wales you can call the Welsh Blood Service on 0800 252 266 or if you live in North Wales call NHS Blood and Transplant (0300 123 23 23). Staff will give you more specific advice about whether or not you can donate blood. For example, not all types of medication or immunisations prevent you from donating.

You should not give blood if:

  • you have a chesty cough, sore throat or an active cold sore
  • you are taking antibiotics or have finished a course of antibiotics in the last seven days
  • you are pregnant or have given birth in the last six months
  • you have had hepatitis A or jaundice in the last 12 months
  • you have had  a tattoo, an ear piercing, body piercingor semi-permanent make up in the last four months
  • a member of your immediate family has had Creutzfeldt-Jakob disease (CJD), a rare condition that affects the nervous system and causes brain damage
  • you have had acupuncture in the last four months, unless this was done within the NHS or by a qualified healthcare professional registered with a statutory body
  • you have received human pituitary extract (a substance used in some growth hormone and fertility treatments before 1985)
  • you have received blood during the course of a medical treatment or procedure since 1980

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

  • a commercial sex worker
  • someone who has injected drugs
  • someone who has haemophilia (a condition that stops your blood from clotting normally)  or another type of blood disorder that required clotting factor treatment
  • someone who has been sexually active in parts of the world where AIDS and HIV are common, such as sub-Saharan Africa
  • a man who has had oral or anal sex with another man (if you are female)
  • a man (if you are male) – with or without a condom

As of November 2011, a man who has sex with men can donate blood provided they have not had anal or oral sex with a man during the past 12 months (even with a condom). Previously, men who had sex with men were not allowed to donate blood.

You should never donate blood if:

  • you have HIV
  • you have ever had hepatitis C
  • you have ever had syphilis
  • you have ever had human t-lymphotropic virus (HTLV)
  • you have ever injected yourself with drugs
  • you have ever worked as a commercial sex worker

Zika Virus
There is a small risk of Zika virus being transmitted via sexual contact. Although the risk is very low, there is now a requirement to ask all donors an extra question in order to reduce the risk of Zika virus in blood donations. This question will be asked during the screening process on the clinic.

Religious beliefs

All major religions in the UK support the principles of blood and organ donation. They also agree these types of donation should always be a matter of personal choice, and that no one should ever be pressured into making a donation.

The NHS Blood and Transplant website has more information about religious perspectives on organ donations.

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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.


After your blood has been collected for donation, it is sent for testing in a laboratory. Here, it is screened for viruses and infections such as HIV and hepatitis.

If the blood passes this screening, it will usually be separated into different components. This means 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. It is usually then stored in a blood bank until needed.

When the blood is needed, a process known as blood transfusion is used to give it to a recipient.

Different components

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

Red blood cells

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

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

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


Platelets are the cells in your blood that help it to clot. They are often used to treat bleeding caused by bone marrow failure. Bone marrow is the spongy tissue inside your bones that helps 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 bleeding caused by leukaemia (a form of cancer that affects the blood cells).

Read more about platelet donation.


Plasma is a yellow-coloured fluid that helps carry all the different types of blood cells. It is usually frozen.

Frozen plasma is used to help replace blood lost during childbirth or heart surgery.

Read more about plasma products.

Terminal illness

As well as saving lives, blood donations can also help improve the quality of life of people with a terminal illness. A blood transfusion may give them the energy to spend time with friends and relatives.

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Cord blood donation

Cord blood is the blood that remains in the placenta and umbilical cord after a baby is born. It can be used to treat many life-threatening conditions.

For example, conditions such as leukaemia (cancer of the bone marrow cells) and problems with the immune system (the body's defence system) can be treated with a cord blood transplant.

After a baby is born, the placenta and umbilical cord are usually thrown away. However, as this is a rich source of stem cells, the NHS Cord Blood Bank was set up in 1996 to collect, process, store and supply cord blood for transplants.

Once the cord blood has been processed and frozen, it can be stored until a patient with a matching tissue type needs a stem cell transplant. Research has shown that units can be stored for up to 20 years.

Mothers must give their consent for the cord blood and any part of the placenta or cord itself to be collected. Without consent, the placenta and cord blood will be thrown away. When giving consent for the donation, the mother gives up all future rights to the donation. You can register your interest in donating your cord blood on the NHS Cord Blood Bank website.

Cord blood can usually only be collected in hospitals where there are specialist trained staff. Currently, these are only to be found in Southern England:

  • Barnet General Hospital
  • Northwick Park Hospital, Harrow
  • Luton and Dunstable Hospital
  • Watford General Hospital
  • St George's Hospital, London
  • University College Hospital, London

This ensures cord blood is handled correctly and stored in the NHS Cord Blood Bank for doctors to use for their patients.

In special cases, cord blood is also collected under the NHS when it is needed for an older child in the same family. These collections are arranged by NHS Blood and Transplant (NHSBT) and attempts are made to make the donation as convenient as possible. Preferably, the donation will be made at the nearest hospital with birthing facilities.

Some private companies also make cord blood collections for individual families for possible future use. However, the NHS does not support this type of collection as the chances of using the cord blood in the future are extremely low.

If you are interested in cord blood donation, or if you want to know more, visit the NHS Cord Blood Bank website.

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Platelet donation

A platelet donation is a relatively new way of donating blood. It involves using special equipment to separate platelet cells from donated blood.

Platelet cells are very useful for treating a range of conditions and situations, including:

  • leukaemia (bone marrow cancer)
  • excessive blood loss
  • people who have just received a bone marrow transplant

The advantage of platelet donations is that a small amount can be used to treat several people. One donation is often enough to treat up to three adults or twelve children.

The disadvantage is that donated platelets can only be stored safely for seven days. This means there is a constant demand for new donors.

Not everyone who can donate blood is able to donate platelets, because you need a higher than average platelet rate in your blood for the donation to be successful. Your platelet rate will be tested before the donation goes ahead.

Do not be alarmed if testing shows you have an average platelet rate and are unable to donate platelets. This is perfectly normal and nothing to worry about.

The donation procedure is similar to regular blood donation except it takes slightly longer (about 90 minutes).

The rules for who cannot donate are similar to those for donating blood. However, you also cannot donate platelets if:

Read more about who can make a blood donation.

Due to the specialised equipment needed to separate platelets from the blood, a donation can only be made at specialised platelet donation centres.

The Welsh Blood Service have a clinic for platelet donors in Talbot Green. There are currently 24 donation centres in England, all located in larger towns and cities. Liverpool and Stoke being perhaps the nearest to North Wales. A full list of donation centres can be found on the NHS Blood and Transplant website.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website nhs.uk
Last Updated: 06/05/2020 12:17:00