Blood donation

Most donated blood is used to help people with medical conditions that need blood or blood products regularly. For example, around 34% of donated red blood cells are used to help treat people with cancer and blood diseases. Medical researchers also rely on donated blood to develop and test new treatments for many conditions, such as blood clots.

Blood groups#

There are four main blood groups: A, B, AB and O. Each is either Rh-positive or Rh-negative.

• O negative blood can be given to almost anyone if necessary.
• Even so, it is always preferable to match the exact blood group to prevent dangerous reactions.

Who can donate blood?#

Healthy adults aged 18 to 75 years who meet the eligibility criteria can donate blood. The procedure is safe and relatively painless.

During a regular donation, you give around 470 mL of whole blood. This is about 8% of the average adult’s blood volume. The body replaces this volume within 24 to 48 hours and replenishes red blood cells in 10 to 12 weeks.

To donate blood, you generally need to:

• Be well, and free of a cold, flu or other illness at the time of donation, with a normal temperature and blood pressure.
• Be aged between 18 and 75 years (other rules may apply if you are already a regular donor).
• Weigh at least 50 kg.
• Meet guidelines designed to protect both the donor and the people who will receive the blood.

Some medications may affect your ability to donate. If you are unsure whether a medication rules you in or out, check with the blood donation service before your appointment.

Eligibility rules can change over time. In the past, some people were unable to donate because of where they had lived during certain periods, owing to the risk of variant Creutzfeldt-Jakob disease (vCJD), the human form of the condition sometimes called “mad cow disease”. Many of these restrictions have since been reviewed and relaxed, so it is worth checking the current rules if you were previously unable to donate.

What happens when you donate#

Donating blood itself takes only around 10 minutes, but you should allow at least an hour for the whole process, which includes a personal interview, recovery time and refreshments. You can donate at a fixed donor center or at a mobile collection unit.

All donated blood is screened for blood-borne diseases such as hepatitis, syphilis and HIV.

How often can you donate?#

You can usually donate whole blood every 12 weeks, but you can donate plasma every 2 weeks.

Types of blood donation#

The main types of donation are:

• Whole blood – a standard donation that contains red cells, white cells, platelets, plasma, antibodies and other components.
• Plasma (apheresis) – plasma is separated from the other components by a special machine, and the red blood cells are returned to the donor in cycles throughout the donation.
• Platelets (plateletpheresis) – done in a similar way to plasma donation, but the red cells and plasma are returned to the donor.

Less common donations include:

• Autologous donation – a person donates blood for their own use, for example before a scheduled operation or transfusion.
• Directed or designated donation – a donor gives blood that will be used for a specific person.

Autologous and directed donations are now rare and occur only in special medical cases. These donations carry the same risks as regular blood donations.

Products made from donated blood#

Donated blood is used to make a variety of products.

From whole blood:

• Red cells – carry oxygen. Most recipients of donated blood are given red cells to boost the oxygen-carrying ability of their own blood.
• Platelets – needed for blood clotting. People who need extra platelets include those with certain diseases and those recovering from a severe hemorrhage (bleeding).

Plasma makes up about 55% of blood. It is the straw-colored liquid that carries red cells, white cells and platelets, and it also contains antibodies and other important proteins. Plasma is processed into a number of products, including:

• Anti-D – helps prevent hemolytic disease of the newborn by protecting a mother who is Rh-negative against the incompatible Rh-positive blood cells of her baby.
• Human immunoglobulin (Intragam) – used to boost the immune system.
• Normal immunoglobulin – used to help prevent hepatitis A (including for travelers or family contacts of someone with the illness).
• Hyper immunoglobulins – used in vaccinations for conditions such as chickenpox, tetanus, cytomegalovirus and hepatitis B.
• Human albumin (Albumex 20) – used to treat protein deficiency.
• Biostate (Factor VIII Concentrate) – used to treat hemophilia A and other bleeding disorders.
• Human coagulation factor IX (Monofix) – used to treat hemophilia B.
• Human prothrombin complex (Prothrombinex HT) – used to treat bleeding disorders.
• Human antithrombin III (Thrombotrol VF) – used to treat a condition marked by premature blood clotting.

Blood donation for medical research#

About 8 out of every 10 people will experience a blood-related disease at some point in their lives, and blood cancers such as lymphoma, leukemia and myeloma (cancer of the plasma cells in bone marrow) make up about 15% of cancers. New treatments for these life-threatening conditions depend on medical research.

Research scientists need donated blood to investigate the causes of blood-related diseases and to test newly developed treatments, including work on:

• Anti-clotting enzymes – certain enzymes help break down and remove blood clots from the bloodstream. Understanding this process may help develop new treatments for life-threatening clots that can cause heart attack or stroke.
• Platelets – investigating how and why platelets stick to blood vessel walls can help explain why conditions such as heart attack and stroke occur.
• Blood stem cells – create blood components such as red cells, white cells and platelets. Malfunctioning stem cells are thought to cause blood-related illnesses such as leukemia, so studying how they work can lead to better treatments.

Donated blood is also used to test the effectiveness of new treatments.

Requirements for research donors#

Requirements for medical research may differ slightly from those for regular blood donors, and some people who do not qualify as regular donors may still qualify for research. To donate blood for medical research, you generally need to:

• Be aged 18 to 60.
• Not be taking anti-clotting or anti-inflammatory medications (such as aspirin, warfarin or ibuprofen).

Your first research appointment#

At your first appointment you receive an information form explaining the purpose of the research and a consent form to sign. The blood collection takes about 15 minutes, is safe, and is performed by a fully trained scientist, nurse or doctor. The amount of blood taken depends on the research project and ranges from 40 to 400 mL. Your body needs only a couple of days to replace 400 mL of blood. A small payment may be offered to help cover transport or other costs.

If you indicate that you would be willing to give blood again, your contact details may be kept on a database so you can be invited to donate around once every three months. You can also ask to receive information on the results of the research project.

If you agree to take part in a research project, you must sign a consent form. The exact wording varies between projects, but it typically covers details such as any possible side effects (for example, mild discomfort or a small amount of bruising around the needle site). Blood given for research is used purely for research, not for transfusion or any other medical purpose. All information you provide is kept confidential, participation is voluntary, and you can change your mind at any stage.

Key points#

• Autologous and directed donations carry the same risks as regular blood donations.
• Plasma also contains antibodies and other important proteins.
• New treatments for life-threatening blood conditions depend on medical research.
• Understanding how clots form may help develop new treatments for life-threatening blood clots.
• Malfunctioning stem cells are thought to cause blood-related illnesses such as leukemia.

Where to get help#