Practical transfusion medicine for dogs and cats (Proceedings)
Veterinary transfusion medicine practices have evolved considerably over the last 10 years as we have come to better understand immunology, infectious disease, and the appropriate use of blood and blood products. Some of our biggest advances in ensuring the provision of a safe blood product has come as a result of our errors including, but not limited to acute immunologic transfusion reactions and delayed non-immunologic transfusion reactions (infectious disease transmission). The following manuscript will provide the reader with some of the keys to providing a safe blood product to dogs and cats in need.
Selecting Canine Donors Based on Blood Type:
Dog Erythrocyte Antigens (DEA) are glycolipids and glycoproteins on the surface of the red blood cell. The presence or absence of these DEA defines the blood type of an individual. The blood type of the "universal" canine blood donor varies dramatically based on individual theory, laboratory investigation, clinical experience, or a combination of these. There are two "poles" of the universal donor typing debate.At one end of the spectrum, is the philosophy that the universal donor is one that is positive for DEA 4 (as are 98% of the population) and negative for all other DEA for which antisera (for typing) exist and negative for all anti-DEA antibody (Ab). This approach to selecting the "universal" canine donor is most likely to minimize the likelihood of an acute hemolytic transfusion reaction, maximize the lifespan of the transfused blood and make future cross match most likely to be compatible with the recipient.
At the other end of the spectrum is the theory that because DEA 1.1 is the DEA clinically implicated most often as a cause of acute transfusion reaction in previously sensitized dogs, this is the only DEA that we must routinely type for. This approach to selecting the "universal" canine blood donor will maximize the size of the donor pool.
Both blood typing systems have their advantages. For the small, private practice setting, the latter system is more economical and more practical. The author recommends performing DEA 1.1 testing on all donors and recipients. Then, only consider using DEA 1.1(-) donors OR use DEA 1.1(+) donors for DEA 1.1(+) recipients and DEA 1.1(-) donors for DEA 1.1(-) or 1.1(+) recipients. Crossmatching is not necessary for the initial transfusion. If additional transfusions are necessary >3-7days later, cross-matching procedures are indicated. Further screening is required to minimize the likelihood of infectious disease transmission.
Additional Testing of Canine Donors:
Numerous selection factors other than blood type are critical to ensuring the safety of canine blood transfusions. Screening for these factors can be somewhat time-consuming and costly; however, if it prevents morbidity or mortality to the donor or the recipient, then the increased effort is well worth the added time and expense. The author's transfusion medicine program follows the 2005 ACVIM Recommendations for Canine and Feline Blood Donor Screening for Infectious Diseases1 . Pitbull dogs and Foxhounds should be considered for exclusion from the donor program due to the relatively high incidence of Babesia sp. and Leishmania sp. respectively. Alternatively, these diseases can be screened for intensively in those breeds. In addition to being free from infectious disease, potential donors should be less than 8 years of age, have a normal CBC, Serum Biochemical Profile, and Urinalysis, no previous medical problems, a body weight greater than 25Kg, no concurrent medications, an appropriate vaccination history, no previous transfusion history, and a personality that will allow for sustained restraint for blood collection. The author currently also evaluates donors for von Willebrand Factor levels. All screening with the exception of blood type and von Willebrand factor level should be repeated on an annual basis.