PetMD Seal

Blood Transfusion Reactions in Dogs

3 min read


There are a variety of reactions that can occur with the transfusion of any blood product. Most reactions usually occur during or shortly after transfusions. Purebred dogs, especially, that have had previous blood transfusions are at a higher risk for severe reactions to transfusion than other dogs.


The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the PetMD health library.


Symptoms and Types


Reaction to a blood transfusion may be classified by one of the following conditions: immune system related; acute reaction (an immediate, sudden reaction); or delayed reaction.


Acute symptoms of a reaction to blood transfusion may include fever, vomiting, weakness, incontinence, shock, collapse, and general loss of transfusion effectiveness. Symptoms of a delayed reaction are usually not directly apparent and result only in a loss of the transfusion’s effectiveness.


Many symptoms vary depending on the exact cause. Transfusion of contaminated blood can result in fever, shock, and septicemia -- an invasion of disease producing bacteria into the bloodstream. Circulatory overload resulting from rapid or excessive transfusion can result in vomiting, cough, and heart failure. Hypothermia, which can stem from transfusion of cold refrigerated blood -- usually in smaller dogs or already hypothermic (abnormally low body temperature) patients -- is evident in shivering and impaired platelet function.




There are several circumstances that may be responsible for a blood transfusion reaction, such as transfusion of a mismatched blood type; transfusion of contaminated blood and consequent blood-born disease from an infected donor; circulatory overload caused by too-rapid or too-large amounts of transfusion; or transfusion of damaged red blood cells which have been improperly stored (i.e., due to excessive heating or freezing). In addition to these causes, the dog’s immune system may react to various components in the donor’s blood. Symptoms will usually surface in the course of three to fourteen days.




Diagnosis of reaction to blood transfusion is based largely on symptoms that show after transfusion. Tests include a urine analysis, retesting of blood type to confirm rejection of donor blood, and a bacteria analysis of the transfused blood.


Symptoms of reaction that result in fever or hypotension (low blood pressure ) may also be diagnosed as inflammatory disease, or may be found to have been caused by an infectious disease.




Related Articles

Low Platelet Count in Dogs

Thrombocytopenia is a medical condition where blood platelets become too low in animals.

Hemoglobin and Myoglobin in Urine in Dogs

Hemoglobin is an oxygen carrier in the red blood cells, which also serves to carry oxygen to the tissues, as well as the pigment that makes the...

Heart (Aortic) Blood Clot in Dogs

Aortic thromboembolism, also referred to as saddle thrombus, is a common heart condition which results from a blood clot dislodging within the...

Anemia (Methemoglobinemia) in Dogs

Under normal conditions, methemoglobin is converted back to hemoglobin, and a balance is maintained. Learn more about Anemia in Dogs at