The NHS blood services run regular
sessions across the country where members of the public are encouraged to donate blood.
Before making a blood donation, the potential donor is asked about their health, lifestyle and history. This is to make sure the donor is fit and well, and because certain groups of people shouldn't donate blood as they have an increased risk of having a blood-borne infection, such as men who have had sex with other men or injecting drug users.
Read more information about who can donate blood.
After blood has been donated, it's always tested for the following infections:
The blood may also be tested for malaria and West Nile virus if the donor has recently spent time in countries where these two conditions are known to be prevalent.
How blood is given
A small sample of your blood is usually needed before a blood transfusion to make sure your blood is compatible with the donor blood. Read more about blood groups.
Blood is usually given through a tiny plastic tube called a cannula, this is inserted into a vein in your arm. The cannula is connected to a drip and the blood runs through the drip into your arm.
Depending on the underlying condition and the type of other treatment needed, some patients may have a larger tube, which is known as a central line, inserted into a vein in their chest. Alternatively, a peripherally inserted central catheter (PICC line) may be inserted in the crook of the arm. These lines can also be used for blood transfusions.
During the transfusion
Most people don't feel anything when receiving a blood transfusion. You'll be observed at regular intervals, but if you start to feel unwell during or shortly after your transfusion, you should tell a member of staff immediately.
Some people may develop a temperature, chills or a rash. These reactions are usually mild and easily treated with paracetamol or by slowing down the blood transfusion.
Severe reactions to blood are rare. If they occur, staff carrying out the transfusion are trained to recognise and treat them. If you have any concerns, discuss them with your doctor, nurse or midwife.
Read more information about risks of blood transfusion.