Pet Factsheets

Blood transfusion - is it right for my pet?

The term blood transfusion covers the administration of a number of blood products, eg red cells as well as whole blood, or just the plasma component. In fact, it is less common for pets to receive a straightforward whole blood donation than a particular component of the blood. Just as for people, there are now animal blood banks where donor pets give blood that is stored to be used in case of emergency. Each unit of blood taken at a blood bank is processed and separated into different parts so that every donation can be used to help multiple pets.

Why does my pet need a blood transfusion?

There are many reasons why a pet might require a blood transfusion. If your vet has advised that your pet needs a transfusion you can be sure that they do. Although the procedure itself is relatively routine, blood donations are treated as precious gifts and used only when necessary. Transfusions can be helpful in many circumstances: anaemia (low levels of red blood cells), blood loss, eg after an accident, or surgery; persistent bleeding due to a blood clotting disorder (which may be a consequence of poisoning); or occasionally low protein levels in the blood.

Is it safe for my pet to receive a blood transfusion?

A blood transfusion is a form of transplant and invoves addition of foreign blood cells into an animal's blood stream. There are, of course, some risks associated with this. There are checks that can be done to identify your pet's blood type and to ensure that the blood that is being given matches as closely as possible to your pet's own blood. Nonetheless, in a small minority of patients, a reaction might occur. In most cases the reaction is not severe and the blood transfusion can continue with careful monitoring. There is the possibility that a severe transfusion reaction might occur and in very rare cases this could be fatal. Reactions are more common in pets that have already received a transfusion in the past. It is therefore important to advise your vet if you know that your pet has previously received a blood transfusion.

There is a very small risk that infections could be present in the donor blood and that these could be transferred to your pet during transfusion. The risk of this is low, as blood from a blood bank is screened for various known infectious diseases before it is used. You must remember that your vet would only recommend a transfusion if it was essential for your pet and they will have weighed up the potential risks against the benefit to your pet.

Where does the blood for a transfusion come from?

In recent years there has been the development of sophisticated blood banks to provide blood for donations in pets. Owners of healthy cats volunteer their pets to give blood donations. These cats are tested to make sure they are fit and healthy and their blood group and type is identified, then blood can be collected under sedation. Blood collected in this way can be separated into a number of components, ie red blood cells and plasma and these parts can be stored. In the case of plasma, storage can be for months to years (if frozen) until needed. If your pet is in need of a transfusion a blood sample from your pet can be tested in practice, or sent to the blood bank where they will identify your pet's blood type and a suitable donor match. The appropriate product can then be sent to your vet for administration.

In some emergency situations, or where access to a blood bank is not available, blood can be collected from a local donor and be administered as a fresh donation. If you have another pet that is healthy it may be that this pet can act as a blood donor. The risk of a transfusion reaction from an un-matched donor is low in cats that have not received a prior transfusion, however, it is ideal that the appropriate testing is done before transfusion to minimise this risk.

How is an animal prepared for transfusion?

Prior to the transfusion a blood sample will be collected from the animal who will receive the transfusion, the recipient. This blood is used to identify the blood type of the recipient and may also be tested against the blood donor to make sure that there is no reaction between the two samples. This is called 'cross-matching' and helps to ensure that is is safe for the patient to receive blood from a specific donor. Cross-matching is most important where your pet has received a previous blood transfusion, and may not be performed where this has not occurred, or in an emergency situation due to the delay in providing life-saving therapy. Pets need to come into the hospital to receive the transfusion. A catheter will be placed in the vein of a leg on the patient to provide a safe route through which the donation is given.

Will my pet be distressed by receiving the transfusion?

Administering the transfusion is relatively straightforward and most pets tolerate the procedure without any problems. Blood transfusions need to be given slowly so your pet will need to stay in hospital for several hours while the transfusion is given, during which time they will be monitored closely to make sure there are no signs of a reaction. It is important the patient stays still during the transfusion and does not pull out the catheter so it may be necessary for your pet to receive a sedative to help them relax.

How will the transfusion help my pet?

Transfusions may be of benefit to your pet in a number of different ways, depending upon the reason for giving a blood product. If your pet is anaemic, they have too few red blood cells. You probably notice that they are often tired and reluctant to exercise. A blood transfusion can provide extra red blood cells to carry oxygen and immediately after the transfusion you may notice a dramatic improvement in your pet. After an accident (such as being hit by a car), or during some operations, your pet may lose a lot of blood through bleeding. A transfusion can replace the lost blood and keep your pet alive long enough for the vet to stop the bleeding and repair the damage. Sometimes transfusions are given to animals that have a problem with blood clotting - in this case fresh blood (taken directly from a donor and given to the patient), or the plasma component of blood, can be used.

Will a transfusion cure my pet?

Most often, a transfusion is not a specific treatment and so is unlikely to cure your pet. Your vet will often be recommending a transfusion to 'buy time' to stabilise your pet long enough to allow them to identify and start treating your pet's underlying problem. It is likely that there will be ongoing investigations and treatment after the transfusion is completed. Immediately after the transfusion (especially if your pet was anaemic before the transfusion) your pet is likely to look much brighter and have more energy. However, the new blood cells won't last more than a few weeks inside your pet so unless the underlying cause of the problem is treated your pet will get worse again.

A blood transfusion, although straightforward procedure, is often life-saving. If you have any particular concerns you should discuss these with your own vet but you can be sure that if they are recommending a transfusion it will be in the best interest of your pet. It is very important that you let your vet know whether your pet has had a previous transfusion as reactions are more common after repeated transfusions. To find out more about blood donation and blood banks visit: