Blood Typing And Cross-matching

By By Lori Luechtefeld

Successful transfusion medicine in the veterinary industry relies heavily on blood typing and crossmatching—and recognizing the difference between the two.

Blood typing focuses on the antigens on the surface of the red cell. Crossmatching focuses on antibodies in the plasma. In a crossmatch, donor red cells are mixed with the plasma of the recipient. If antibodies exist in the recipient plasma to antigens on the red cells of the donor, transfusion reactions can occur.

Ann Schneider, DVM, director of Eastern Veterinary Blood Bank in Severna Park, Md., says that veterinarians today are more willing to blood-type and crossmatch their patients than they have been in the past.

“This is a great benefit to the patients, the veterinarians and the blood banks, as it not only reduces the possibility of a transfusion reaction, but it also helps us allocate limited resources to benefit the largest number of patients.”

Anne Hale, DVM, owner and director of Midwest Animal Blood Services Inc. in Stockbridge, Mich., says that improvements in point-of-care blood typing technologies continue to enhance veterinary practitioners’ ability to blood-type recipients and provide type-matched transfusions for their patients.

“Crossmatching test kits are available to allow point-of-care compatibility testing for the dog and cat,” she says. “Field practitioners must become aware of their point-of-care options for typing and crossmatching.”

Dr. Hale says continued data collection in dogs and cats suggests that the current understanding of common blood types may not be complete.

“Currently, we recognize nine transfusion-significant blood groups in dogs and four transfusion-significant blood groups in cats,” she says.

“We still suggest the utilization of full dog erythrocyte antigen type for all canine donors and DEA 1.1 evaluation in the field for all canine recipients,” she adds. “This will allow every practitioner to safely transfuse their canine patients with minimal risk of transfusion reaction. In the cat, it is apparent that we need to blood-type and crossmatch every donor recipient pair to provide our feline patients with safe and effective transfusion medicine.”

Larry DeLuca, EdD, MD, president and director of Sun States Animal Blood Bank in Wilton Manors, Fla., says that his organization also recommends typing for DEA 1.1 for all canine patients, and crossmatching for every unit transfused.

“DEA 1.1 is the most likely antigen to cause serious transfusion reactions,” he says. “It is also the only antigen for which rapid bedside tests are available so that results can be used immediately.

“For patients who receive chronic transfusions, more detailed typing may very well be appropriate,” he adds. “Of course, the nature of these patients is that their illnesses are chronic, and so one can afford to wait the few extra days for complete typing information. Fortunately, these are also the patients in whom this information is the most valuable.”

Rebecca Nusbaum, CVT, VTS (ECC), director and donor coordinator at HemoSolutions in Colorado Springs, Colo., says negative blood—which is also referred to as universal blood—is the blood type that is in greatest demand among clinics.

“It is compatible with all canine blood types, but unfortunately, it is also the hardest to come by,” she says. “Only 1 in 15 dogs will have this blood type.

“Negative blood is usually the most expensive because it is in higher demand and fewer dogs have this blood type,” Nusbaum adds. “Positive blood is generally less expensive at most blood banks. Because of negative blood’s availability, it is in the clinic’s best interest to be able to offer blood typing and both positive and negative blood products so that animals receive their specific blood type.”

Nusbaum notes that not only will this approach save money and enable patients to continue treatment, but it will also free up negative blood supplies for patients that are truly negative recipients or are in urgent need of a transfusion.

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