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Before You Donate

Blood safety starts with you!

Please read all the information provided here carefully before you donate blood, plasma or platelets.

The reason for this is two-fold:

  • to remind you that we rely on your honesty to keep the blood supply safe.
  • to provide you with the information you need about the risks of donation so that you can make an informed decision about donating blood, plasma or platelets.

For further advice on these issues, please contact the WBS helpline on 0800 252 266, your GP or call NHS 111.

So that we can ensure a safe blood supply for patients please inform us if you become unwell within two weeks following your donation or if you believe your blood should not be transfused to a patient.

Possible consequences/risks of giving blood, plasma or platelets

For the vast majority of people, blood, platelet or plasma donation is a simple and trouble-free experience. There are however some risks you need to be aware of. Below is a description of these adverse consequences of donation and the recorded incidences at the WBS:

All stated adverse event rates below relate to WBS performance data 01/04/2016 – 31/12/2021

Minor bruising of the arm after blood, platelet or plasma donation is common, usually harmless and will fade within a few days. To help reduce the chances of bruising you will be asked at clinic to apply pressure to the venepuncture site once your donation is complete. You should avoid heavy lifting or manual work with your donor arm for at least twelve hours after donation.

Bruising occurs at a rate of 1 in 104 attempted venepunctures at the WBS. Sometimes more significant bruising of the arm develops and can occasionally cause symptoms that include nerve irritation, swelling or restricted movement. If bruising, pain or discomfort becomes severe, or does not resolve within seven days, you should seek advice using the details below.

Read more here.

Some donors experience pain in their donor arm following donation (1 in 378). This is quite common, should settle within 24 hours and the arm should be used normally. Infrequently, inserting the needle may cause more significant arm discomfort post-donation – almost all of these settle within a few weeks of donation.

In order to reduce the risk of these complications please inform the clinic staff of you experience any of the following in order for your donation to be discontinued:

  • Pain which is more than mild discomfort
  • Pain that radiates up to your shoulder or down into your hand
  • Pins and needles in the arm or the hand.


Some donors may feel faint (light-headed, dizzy, hot, sweaty, trembling, shaky or nauseous) – 1 in 66 clinic attendances. As a consequence of giving blood, platelets or plasma a small number of donors may actually faint (1 in 683). Some donors that do faint may also injure themselves during the faint (1 in 13,800).

There are a variety of reasons for this and there are things that you and our staff can do to help reduce the risk of this happening. Please follow the advice given to you. If you are at all concerned about feeling faint or fainting please ask to speak to the nurse in charge. Our staff are trained to care for you if you do feel faint and will make sure you do not leave the clinic until you are feeling well. Occasionally you may feel faint or actually faint quite a long time after donation, even the following day, this is known as a “delayed faint” (1 in 2,003).

If you do experience a delayed faint it is important that you ring the WBS helpline to report it. After donation please drink plenty of non-alcoholic fluids, avoid strenuous exercise and avoid exposure to heat e.g. saunas and hot baths. Also, avoid any activity that may be hazardous to you or others should you start to feel weak or light-headed. If you do feel faint after leaving the clinic, lie down straight away and as you start to feel better ensure you drink plenty of fluids. If your symptoms persist or you actually faint please seek advice using the details below. …read more

Rare risks associated with blood, plasma and platelet donation

Although extremely uncommon, other problems can occur and are described below.

All stated adverse event rates below relate to WBS performance data 01/04/2016 – 31/12/2021

  • Short lived symptoms suggestive of nerve irritation post donation (1 in 40,826)
  • Arm discomfort persisting one year or more post donation: caused by – tendon injury (1 in 530,732), nerve injury (1 in 176,911)
  • Arterial puncture (1 in 15,610)
  • Complications related to an arterial puncture: arterio-venous fistula (none recorded at WBS), compartment syndrome (none recorded at WBS), brachial artery pseudo-aneurysm (none recorded at WBS)
  • “re-bleed” (bleeding from the needle insertion site after donation) (1 in 8,701)
  • Localised infection or inflammation (thrombophlebitis or cellulitis) (1 in 132,683)
  • Axillary vein deep vein thrombosis (1 in 530,732)

Donors are asked to declare all medical problems during the health screening process. Donors with a known history of significant heart (cardiovascular) problems are deferred from donating. Despite this, there is still a very small chance that donors may have an unexpected adverse cardiovascular event during or post donation. These include:

  • Acute cardiac symptoms like chest pain (none recorded at WBS)
  • Heart attack / cardiac arrest (none recorded at WBS)
  • Mini-stroke or stroke (1 in 520,732)
  • Localised allergic reactions e.g. reactions to the arm cleaning agent (1 in 9,151)
  • Generalised allergic reactions (1 in 530, 732)
  • Death (none recorded at WBS)

Our staff are trained to recognise these rare complications and you will be given immediate treatment and appropriate advice. If issues relating to such an incident occur after you leave the session you should contact the WBS helpline on 0800 252 266, your GP or NHS 999 or 111 for advice.


To be read by whole blood donors

Each blood donation contains approximately 240mg of iron and it can take approximately 4-6 months to replace this by eating a diet rich in iron. Young donors, pre-menopausal female donors, donors who donate very regularly and donors whose diets have a low iron content are at greater risk of developing iron deficiency as a result of blood donation. The time taken to replace iron lost by blood donation can be reduced by taking over the counter iron containing supplements e.g. multivitamins containing iron.

To be read by plasma and platelet donors only

As part of the informed consent process, at registration for platelet or plasma donation by apheresis, one of our nurses will spend time with you to discuss the apheresis donation procedure, including the possible risks of donating by apheresis. Leaflets giving more detail will be available. For the vast majority, giving platelets or plasma by apheresis is a simple and trouble-free experience. However, there are some risks you need to be aware of:


All stated adverse event rates below relate to WBS performance data 01/04/2016 – 31/12/2021

An anti-coagulant is used throughout the platelet/plasma apheresis donation process to stop your blood clotting within the apheresis machine. The cyclic draw and return of blood to you during the donation process means that a small amount of the anticoagulant is returned in your blood.

This will not cause you to be anti-coagulated but can cause minor reactions with symptoms including tingling, vibration, restlessness, chilling and altered taste (1 in 1,101). You should inform a member of staff if you experience any of these symptoms so appropriate action, such as pausing the apheresis machine or slowing the return flow, can be made. If symptoms persist or become uncomfortable we will stop your donation.

The citrate containing anti-coagulant solution has a mild effect on cardiac muscle function during the donation, which may cause harm if an underlying heart condition is present. To safeguard you we record your pulse rate and rhythm and if necessary we will defer your donation and advise you to visit your GP for further assessment.

You may experience this during the first few cycles of the apheresis donation flow. As the blood leaves the body to be processed in the donation machine it will start to reduce in temperature. This reduction in temperature may be noticed when the blood is returned in the form of chilling or shivering.

Studies have shown that regular platelet donors show a drop in their own platelet levels which is more marked in regular long term donors. This should have no implication for your health and is an expected finding.

Iron deficiency

Regular apheresis donors may become iron deficient. At each apheresis donation, you may lose up to 100ml of blood in the harness and sample pouch. So if you donate at a maximum frequency of 26 times per year, you could lose up to 2,600ml of blood, the equivalent to 4-5 whole blood donations. The finger prick test we do before your donation is to check your haemoglobin level but does not indicate whether your iron stores are healthy or depleted. You cannot donate whole blood as well as being an apheresis donor at the same time …read more

Air embolism

This is the inadvertent entry of air into your blood circulation. There are safety checks in place to ensure that the risks of this occurring are as low as possible. This has not occurred at the WBS to date.

Red cell loss

On occasion we may be unable to return your blood to you – this means a loss of up to 200mls of your blood. This may occur if you experience a side effect whilst donating e.g. feeling faint, developing a bruise or haematoma. More rarely there may be issues with your red blood cells (haemolysis) during the apheresis procedure and we will not return your blood to you should this occur (this has not occurred at WBS to date).


The donation process

When you volunteer to give blood, plasma or platelets for the first time your details will be registered with the Welsh Blood Service (WBS).

All information relating to you and your donation is treated confidentially and stored securely on our database in accordance with current Data Protection Legislation and the Privacy Statement on the WBS website.

The first step when you attend the donation clinic is to register you. Then, a member of our team will show you how to use the touch screen to complete the Self-Administered Health History, which will tell us about your general health and lifestyle.

We want to make sure you are fit and well enough to donate and that your blood, plasma or platelets are safe to give to a patient.

In strict confidence a member of our staff will discuss your Self- Administered Health History with you to assess your suitability.

We will take a small drop of your blood from your finger to check your haemoglobin level. If this shows you are unable to donate today, a blood sample will be offered and we will write to you and advise you what to do next.

If you are a plasma or platelet donor, prior to your first plasma or platelet donation appointment, you will be asked to give informed consent to donate plasma or platelets using a cell separator machine. After health screening blood, plasma and platelet donors will be asked to sign a declaration in the presence of a staff member.

By signing you are agreeing that:

  • You have read and understood this leaflet and the other information provided
  • You have read, understood and completed the Self–Administered Health History
  • You understand the nature of the donation process and the possible risks involved in giving blood, plasma or platelets as explained in this leaflet
  • You have received satisfactory answers to any questions you might have
  • You are, to the best of your knowledge, not at risk of transmitting HIV, hepatitis or other infections
  • All the information provided is true and accurate, to the best of your knowledge.

And you are giving consent for:

The WBS to hold your details on their database in accordance with the terms of relevant Data Protection legislation. Further information is provided in our leaflet ‘Your information rights: collecting data and access to your Welsh Blood Service record’ and the privacy notice on our website. For the purpose of safety, once entered into our donor database we are required by law to retain and potentially process your information indefinitely.

  • Your blood to be tested for HIV and other conditions as listed in this leaflet and to be informed should any of these tests give a positive result
  • Your blood to be used for the benefit of patients (either directly or indirectly)
  • The WBS to establish your blood group and if necessary your white cell and/or platelet type
  • The WBS to store a small sample of your donation for further testing, if required
  • The WBS to contact you directly or through a third party in order to carry out donor satisfaction surveys or other work related to service improvement
  • The WBS to contact you during blood/platelet/plasma stock shortages to ask for your support.

You may also be asked to give consent for extra tests to be performed or to allow your donation to be used for a particular purpose.

You will be asked to sit in a donation chair where we will check your details. A pressure cuff will be placed around your arm (helps to make the vein more visible) and the needle insertion area will be cleaned with antiseptic. A needle attached to a blood bag, plasma/platelet tubing set will then be inserted into your vein. During your donation you will be encouraged to open and close your hand as this helps the blood flow smoothly.

Throughout your donation our staff will keep a close eye on you to make sure everything is fine. If there are any concerns or you are not happy to continue we will stop the donation early so it is important that you let us know.

It usually takes five to ten minutes to complete your blood donation of just under a pint. It can take up to 90 minutes to complete a platelet donation and up to 50 minutes to complete a plasma donation. At the same time blood samples are taken (from the blood collected so no extra needles are needed).

After the donation the needle will be carefully removed from your arm and a dressing and bandage will be applied. During this time you will be shown how to apply pressure to the needle site as this is important in helping to prevent bruising

After donating blood, you will be asked to rest on your donation chair for a short time to make sure all is well before you move to the refreshment area. It is important to replace the fluid you have lost so please give yourself at least ten minutes in the refreshment area and drink up!

After donating plasma or platelets a rest is not routinely required unless indicated by yourself or a staff member. Refreshments are offered before, during and after your plasma/platelet donation.

Testing your donation

Your blood group is checked each time you donate. We also test your blood for HIV, hepatitis B, hepatitis C, hepatitis E, syphilis and HTLV*. If your donation gives a positive result for any of these tests you will be contacted and offered further advice and your donation will have to be destroyed.

Extra tests are carried out on some donations either because of information provided by you e.g. travel history or to meet the special needs of certain patients e.g. babies. These tests may include malaria testing and more detailed blood grouping.

A full blood count is performed at every platelet donation.

*Human T Lymphotropic Virus can cause serious blood and nervous system disease. HTLV is known to be transmissible through transfusion.

Using your donation

The vast majority of donations are used for patients e.g. after blood loss or cancer treatment.

We would like donors to know that their donation may also be used for purposes other than for direct transfusion to patients. This may be for quality assurance, education, training, development or authorised research, which has been approved by an ethics committee. We may also use the donation in the commercial preparation of healthcare-related products within WBS or by other organisations.

The WBS will always ensure that there is no implication for your health or welfare, you will not be identifiable, and any income received by us will be used to offset WBS cost and thus represent a benefit to the National Health Service in Wales.

Did you remember to check your eligibility? It may save you an unnecessary trip.

Take the quiz

Occupations and hobbies

Some occupations/hobbies, examples listed below, can increase the risk of injury should you become unwell after donating. Please inform our clinic staff if you intend to participate in any of the following activities within the next 36 hours.

  • Drive a HGV, crane, minibus, bus or train
  • Emergency response vehicle driver
  • Fire crew
  • Climb ladders or scaffolding
  • Working as aircrew, a pilot or an Air Traffic Controller (including military personnel)
  • Work underground
  • Diving
  • Parachuting
  • Motor sport
  • Climbing

Compliments and concerns

We are committed to providing a high-quality service to our donors and value your feedback. You can help us to improve our service by completing a Compliments and Concerns leaflet which you will find in the refreshments area.

If you are unhappy with our service it is often best to raise the issue as soon as possible. Please ask to speak to the person in charge of the donation clinic who will try to resolve the problem with you.

Alternatively, you can email us at or call us on 0800 252 266.

If you have any questions about any information please ask a member of staff who will be happy to help.