Most people are aware of the existence of blood banks where donated blood and blood products are stored until they are needed by a sick or injured person. These blood banks save many lives each year, and are supported by people who take the time to donate blood for no other reason but to help others. Nowadays, similar blood collection and storage facilities for pets can be found across the United States, offering similar life-saving services to pets that suffer from illness or injuries involving blood loss. Some blood banks keep a number of pets as donors, but many blood products come from cats and dogs whose pet parents bring them to the center to have blood taken. Some blood banks even offer large pet blood products.
Dogs that donate blood need to be in excellent health, aged between one to eight years, and over 35lbs in body weight. They also need to be able to lie quietly for ten to fifteen minutes while blood is collected. Their vaccinations and parasite control treatments must be up-to-date; before they donate, their blood is tested for a number of infectious diseases. They undergo a full physical examination and if all is well, 225mls to 450mls of blood is taken from their jugular vein. After the donation, dogs are given treats and cuddles. The blood is sorted by blood type and it may be separated into its components for storage.
Just like humans, pets have different blood types that differ based on the antigens or markers on the surface of the red blood cells. Dogs have thirteen blood types, but the most important one is DEA 1. These antigens are important because they can trigger transfusion reactions if the wrong blood is given to a pet. If a dog's blood cells don't have a particular antigen on them and they receive blood that does have that antigen, their immune system makes antibodies to the foreign cells. Should they receive another blood transfusion of that type, the red cells are destroyed and the dog can suffer a transfusion reaction. In a transfusion reaction, the recipient's immune system destroys the new red blood cells. This can cause sudden severe shock and collapse. Sometimes the reaction is delayed and not quite so easy to identify – the dog will lose any benefits of the transfusion and they'll again appear anemic. This is why dogs should ideally be blood-typed before receiving a blood transfusion. If that's not possible, then it's safest to give DEA 1 negative blood.
Transfusion medicine in cats is a bit different. Our feline family members have two major blood groups, known as types A and B. Type A cats have naturally occurring antibodies to B antigens, and Type B cats have naturally occurring antibodies to A antigens. This means that a reaction is likely to occur on the first transfusion so blood group testing should be done on any cat that needs a blood donation.
Donor cats should be healthy, 10lbs in weight, and up-to-date with routine treatments. They're less likely to sit still than a dog so they're sedated for blood collection. The amount of blood taken is around 5mls per lb. bodyweight.
Blood transfusions are another example where treatments that are well established in people can be adapted to help our dogs and cats. If you're considering donating your pet's blood, contact your nearest animal blood bank for more information.